Long-term impacts of rising sea temperature and sea level on shallow water coral communities over a ~40 year period.

Effects of combined rising sea temperature and increasing sea level on coral reefs, both factors associated with global warming, have rarely been addressed. In this ~40 y study of shallow reefs in the eastern Indian Ocean, we show that a rising relative sea level, currently estimated at ~11 mm y-1, has not only promoted coral cover but also has potential to limit damaging effects of thermally-induced bleaching. In 2010 the region experienced the most severe bleaching on record with corals subject to sea temperatures of >31 °C for 7 weeks. While the reef flats studied have a common aspect and are dominated by a similar suite of coral species, there was considerable spatial variation in their bleaching response which corresponded with reef-flat depth. Greatest loss of coral cover and community structure disruption occurred on the shallowest reef flats. Damage was less severe on the deepest reef flat where corals were subject to less aerial exposure, rapid flushing and longer submergence in turbid waters. Recovery of the most damaged sites took only ~8 y. While future trajectories of these resilient reefs will depend on sea-level anomalies, and frequency of extreme bleaching the positive role of rising sea level should not be under-estimated.

How muscle relaxation and laterotrusion resolve open locks of the temporomandibular joint. Forward dynamic 3D-modeling of the human masticatory system.

Patients with symptomatic hypermobility of the temporomandibular joint report problems with the closing movement of their jaw. Some are even unable to close their mouth opening wide (open lock). Clinical experience suggests that relaxing the jaw muscles or performing a jaw movement to one side (laterotrusion) might be a solution. The aim of our study was to assess the potential of these strategies for resolving an open lock and we hypothesised that both strategies work equally well in resolving open locks. We assessed the interplay of muscle forces, joint reaction forces and their moments during closing of mouth, following maximal mouth opening. We used a 3D biomechanical model of the masticatory system with a joint shape and muscle orientation that predispose for an open lock. In a forward dynamics approach, the effect of relaxation and laterotrusion strategies was assessed. Performing a laterotrusion movement was predicted to release an open lock for a steeper anterior slope of the articular eminence than relaxing the jaw-closing muscles, herewith we rejected our hypothesis. Both strategies could provide a net jaw closing moment, but only the laterotrusion strategy was able to provide a net posterior force for steeper anterior slope angles. For both strategies, the temporalis muscle appeared pivotal to retrieve the mandibular condyles to the glenoid fossa, due to its' more dorsally oriented working lines.

Validity of functional diagnostic examination for temporomandibular joint disc displacement with reduction.

The choice of approach for diagnosing temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDR), viz. functional examination or TMJ imaging, is debatable and complicated by findings of low agreement between these approaches. Our aim was to investigate the validity of functional ADDR diagnostics using clinical examination and opto-electronic mandibular movement recordings versus magnetic resonance imaging (MRI). 53 participants (32 women and 21 men, mean age ± s.d. of 28.7 ± 10.1 years) underwent a clinical examination, mandibular movement recording and MRI of their TMJs within 1 month. All were performed and analysed in a single-blind design by different experienced examiners for each technique. The sensitivity and specificity of each functional diagnostic method was calculated, with MRI as the gold standard. Anterior disc displacement with reduction was diagnosed in 27.6% of the TMJs clinically, in 15.2% using the movement recordings and in 44.8% on MRI. The specificity of the clinical examination for diagnosing ADDR was 81.0%, and of the movement recordings, 96.6%. The sensitivity was 38.3% and 29.8%, respectively. The chance of having a false-positive functional diagnosis of ADDR compared with MRI is low, and disagreement between the functional methods and MRI is mainly due to the high number of MRI diagnoses in asymptomatic subjects. In view of the fact that ADDR becomes clinically relevant only when it interferes with TMJ function, the functional diagnostic approach can be considered benchmark in ADDR recognition.

Validity of the Oral Behaviours Checklist: correlations between OBC scores and intensity of facial pain.

The first purpose of this study was to translate the Oral Behaviours Checklist (OBC) into Dutch and to examine its psychometric properties. The second purpose was to examine the correlations between scores on the OBC and facial pain, while controlling for the possible confounding effects of psychosocial factors, such as stress, depression, somatisation and anxiety. The OBC was translated, following the international RDC/TMD consortium guidelines. Its psychometric properties were examined by assessing the test-retest reliability and concurrent validity [correlations between the OBC and the previously developed Oral Parafunctions Questionnaire (OPQ)]. Participants were 155 patients with TMD (77% female; mean age and s.d. = 43.6 and 14.4 years). The translation of the OBC into Dutch proceeded satisfactorily. The psychometric properties of the Dutch OBC were good; test-retest reliability was excellent (ICC = 0.86, P < 0.001). Concurrent validity was good: the correlation between the OBC and OPQ was high (r = 0.757, P < 0.001), while the correlations between individual items ranged from 0.389 to 0.892 (P < 0.001). Similar to previous Dutch studies using the OPQ, no significant correlation was found between oral parafunctions and facial pain (r = 0.069, P = 0.892). No significant correlations could be found between oral parafunctional behaviours and facial pain.

[Distinguishing temporomandibular pain from other types of orofacial pain based on a questionnaire]. / Onderscheid tussen temporomandibulaire pijn en andere vormen van orofaciale pijn op basis van een vragenlijst.

This study investigated whether, apart from the usual tools for the diagnosis of temporomandibular pain, a questionnaire can distinguish between temporomandibular pain and other types of orofacial pain, based on the biopsychosocial model. 509 patients, who reported orofacial pain in an online questionnaire, were divided into 2 groups based on a clinical examination: patients with temporomandibular pain and patients with orofacial pain in whom temporomandibular pain was excluded. Logistic regression analyses showed that the 2 patient groups did not differ from each other with regard to the majority of biological and psychological aspects of the biopsychosocial model. However, patients with temporomandibular pain reported bruxism and non-specific pain more often, and reported a higher intensity of pain. This study showed that a questionnaire can aid in distinguishing patients with temporomandibular pain from patients with other types of orofacial pain.

Oral health-related quality of life in patients with tooth wear.

The aim of this study was to investigate the impact of tooth wear (TW) on patients' oral health-related quality of life. A total of 198 participants were included in the study. They belonged to the following four different diagnostic categories: 51 patients with TW, 46 patients with painful temporomandibular disorders (TMD), 43 complete denture wearers and 58 healthy controls. The Dutch version of the Oral Health Impact Profile (OHIP-NL) was used to assess the patients' oral health-related quality of life. The results of the study show that patients with TW have an impaired oral health-related quality of life compared with healthy controls (P < 0·001). Furthermore, the impact of TW and of edentulousness do not differ significantly, while both of these oral conditions seem to have a lower impact on quality of life compared with painful TMD (P < 0·05). It was concluded that TW has a negative impact on patients' quality of life. This impact is comparable with that of edentulousness.

Improvement in patients with a TMD-pain report. A 6-month follow-up study.

UNLABELLED: Even though chronic TMD pain tends to persist in most patients, some chronic patients show improvement. It is largely unknown which factors contribute to the improvement of chronic pain. The aim of this study is to investigate which factors, from a biopsychosocial perspective, help to predict improvement in patients with a report of TMD pain. METHODS: Subjects with a report of TMD pain were recruited in seven TMD clinics. They received a baseline questionnaire which included a wide range of possible predictors for improvement. After 6 months they received a follow-up questionnaire which included a measure to determine which participants were 'improved' or 'not improved'. To study which predictive variables were associated with improvement, multiple regression models were built. RESULTS: From the 129 patients who responded to the baseline questionnaire, 100 patients also filled in the follow-up questionnaire (85% women, mean age (years) ± s.d. = 46·0 ± 13·8). Fifty percentage of these subjects had improved at the 6-month follow-up. Pain duration was the strongest (negative) predictor for 6-month improvement (P = 0·009). Also the number of care providers (P = 0·017) and the degree of hindrance on function (P = 0·045) helped to predict improvement. CONCLUSIONS: The duration of the TMD-pain complaint, the number of care practitioners attended and the degree of hindrance on function (negatively) helped to predict 6-month improvement. No evidence is found to support the role of psychological or social factors on the improvement in patients with a report of TMD pain.

Disc displacement within the human temporomandibular joint: a systematic review of a 'noisy annoyance'.

To describe the scientific literature about the diagnosis, prevalence, aetiology, natural course and possible treatment modalities of disc displacements within the temporomandibular (TM) joint. PubMed was searched for specific indexing terms. The search yielded 1211 papers. After screening according to title and abstract, 695 papers were excluded, and after full-text reading, 107 papers remained. Hand-searching of the reference lists resulted in an extra 47 papers. Thirteen studies, published since the literature search was carried out, were also included, resulting in 167 papers for this review. A disc displacement is a highly prevalent derangement within the TM joint, with reported prevalence ranging from 18% to 35% in the general population. A disc displacement with reduction is mostly a stable, pain-free and lifelong condition of the joint. In only a small minority of patients, the disc loses its capacity to reduce on opening. Surprisingly, only in rare cases, the loss of disc reduction is accompanied by signs and symptoms of a closed lock (viz. a painful and limited mouth opening). These signs and symptoms have a tendency to reduce and in many cases to resolve within months. The favourable natural course of disc displacements only warrants active treatment for symptomatic disc displacements without reduction. The primary treatment option is a conservative, non-surgical treatment focusing at speeding up the natural process of alleviation of pain and of improvement in mouth opening. For most patients, a disc displacement is just a pain-free, lifelong lasting, 'noisy annoyance' from their TM joint.

Developing abbreviated OHIP versions for use with TMD patients.

The aim of this study was to evaluate the psychometric characteristics of three versions of the Dutch Oral Health Impact Profile (OHIP-NL), for clinical use with temporomandibular disorder (TMD) patients. To that end, two abbreviated OHIP versions (OHIP-NL14 and OHIP-NL5) were developed by respectively selecting 14 and five items from the officially translated and culturally adapted original 49-item OHIP-NL questionnaire. A total of 245 consecutive patients, referred by their dentist to the TMD clinic of the Academic Centre for Dentistry Amsterdam (77% women; mean age ± s.d. = 41·0 ± 14·9 years), completed the Research Diagnostic Criteria for TMD (RDC/TMD) axis II questionnaire and the OHIP-NL. Reliability and validity of all three OHIP versions were compared, and their associations with four psychological axis II variables, indicating the level of impairment of patients with TMD, were examined. According to guidelines for clinical application, internal consistency scores were sufficient for OHIP-NL and OHIP-NL14, but insufficient for OHIP-NL5. Test-retest reliability (n = 64) was excellent for OHIP-NL and OHIP-NL14 and fair to good for OHIP-NL5. For all three versions, there was evidence for score validity: associations between OHIP summary scores on the one hand and validation variables and other RDC/TMD axis II variables on the other hand met the expectations and were statistically significant (P < 0·001). In conclusion, the OHIP-NL and OHIP-NL14 both performed comparatively well and better than the OHIP-NL5. When the length of the questionnaire (i.e. the time needed for its completion) is an issue, the OHIP-14 would therefore be the preferred version.

Social support in chronic pain: development and preliminary psychometric assessment of a new instrument.

Satisfaction with social support (pain-relevant social support) may influence pain experience and behaviour in patients with chronic pain. Prior studies on measurement of social support, however, have been limited by the use of general, rather than of pain-specific assessment instruments. In this study, a new pain-relevant social support instrument, the Social support and Pain Questionnaire (SPQ), is presented together with an evaluation of its psychometric properties. A literature search was performed to establish different aspects of social support. For each of the six aspects found, one item was selected for inclusion in the new questionnaire. The draft version of the questionnaire was field tested. Thereafter, the psychometric properties of the SPQ were assessed in 250 patients with oro-facial pain. Principal component analysis (n=250) showed that the SPQ had a one-factor structure. The test-retest reliability of the SPQ (in a subsample of 54 patients) was fair-to-good (R=0·70; P<0·000). Convergent validity, as compared with a non-specific social support instrument, was good (n=140; R=0·54; P<0·000). The SPQ is a valid and reliable instrument, which offers the possibility to explore the patient's satisfaction with pain-related social support. With the SPQ, a useful tool to assess the influence of social support in patients with various types of pain is provided.

[Synovial chondromatosis of the temporomandibular joint. A systematic review of the literature on its characteristics]. / Synoviale chondromatose van het temporomandibulaire gewricht. Een systematisch literatuuronderzoek naar de kenmerken.

Synovial chondromatosis of the temporomandibular joint is a disease which occurs rarely. A systematic review of the literature was carried out to identify its demographical, etiological, radiological, and clinical characteristics. A total of 191 case presentations were discovered. The mean age of patients was 47. The disease has been identified more frequently in women than in men. A part from pre-auricular swelling, the most frequently reported clinical characteristics resembled those of temporomandibular disorders. Abnormalities on radiographs were often evident. Insufficient evidence was found that trauma or rheumatoid arthritis plays a role in the development of this disease. Given the similarities with temporomandibular disorders, synovial chondromatosis should be considered in the differential diagnosis of patients suffering from complaints of temporomandibular dysfunction.

[Oral health impact profile. an instrument for measuring the impact of oral health on the quality of life]. / Oral health impact profile. Meetinstrument voor de invloed van de mondgezondheid op de levenskwaliteit.

A Dutch-language version of the Oral Health Impact Profile, a questionnaire by means of which the impact of oral health on the quality of life of patients can be determined, was developed and subsequently psychometrically tested among a group of patients with complaints concerning missing dentition or their dentures. In addition, a shortened version of this so-called OHIP-NL49, the OHIP-NL14, was psychometrically tested among a group of patients with temporomandibular disorders. The psychometrical characteristics of both the OHIP-NL49 and the OHIP-NL14 were very good: both the reliability and the validity were high. The conclusion was, that the OHIP-NL49 and the OHIP-NL14 are well suited for determining the impact of oral health on the quality of life.

[Oral kinesiology and the quality of life]. / Orale kinesiologie en levenskwaliteit.

In a comparative study, the influence of oral health on the quality of life was investigated for people with temporomandibular pain, people with tooth wear and people with complete dentures. To this end, the study made use of the Oral Health Impact Profile. Both the total score and the scores on 4 of the 7 domains of the Oral Health Impact Profile were significantly higher in the research group with temporomandibular pain than in the research groups with tooth wear and complete dentures. These results suggest that among people with temporomandibular pain the influence of oral health on the quality of life is more negative than among people with tooth wear and among people with complete dentures. This result can probably be linked with the general finding that patients with temporomandibular pain bear a relatively high psycho-social burden.

The effect of raising the bite without mandibular protrusion on obstructive sleep apnoea.

It has recently been suggested that wearing a maxillary occlusal splint (i.e. a hard acrylic resin dental appliance that covers the occlusal surfaces of the maxillary dentition and that is being indicated for the treatment of, e.g. temporomandibular pain) may be associated with a risk of aggravating obstructive sleep apnoea (OSA). The present study tested the hypothesis that raising the bite without mandibular protrusion in OSA patients is associated with an increase in the apnoea-hypopnoea index (AHI). Eighteen OSA patients (13 men; 49·5 ± 8·1 years old) received a mandibular advancement device in 0% protrusion of the mandible (0%MAD). The MAD caused a bite rise of 6 mm as measured interincisally. Polysomnographic recordings were obtained at baseline and with the 0%MAD in situ. No statistically significant difference in AHI was noted between the baseline night and the 0%MAD night. However, nine patients had an aggravation in AHI during the night they used the 0%MAD. Taking into account the previously established smallest detectable difference of 12·8 in AHI, the AHI increased in only two of the patients. The outcomes of this study suggest that an increased jaw gape without mandibular protrusion might be associated with a risk of aggravation of OSA for some, but not for all OSA patients. Dental practitioners should be aware of this possible association when treating patients with oral devices that raise the bite.

Some remarks on the RDC/TMD Validation Project: report of an IADR/Toronto-2008 workshop discussion.

A large-scale, multi-site study has been performed to examine the reliability and validity of the research diagnostic criteria for temporomandibular disorders (RDC/TMD) and to suggest revisions of the current RDC/TMD. During an International Association for Dental Research (IADR) Workshop in July 2008, preliminary results of this RDC/TMD Validation Project were presented. One of us was invited to be the critical discussant of the Workshop session in which the Study Group's papers were presented. This article is based on that contribution. One of our concerns relates to the possible circularity and bias, introduced by incorporating the RDC/TMD tests under investigation into the criterion examination. This may have had serious consequences for the outcomes of the validity study as well as for the proposed revisions of the diagnostic algorithms. In addition, a more detailed description of the process of replacing the RDC/TMD tests by other tests is needed. Further, to come to a revised RDC/TMD, it is crucial to know not only how the test outcomes are capable of discriminating between patients with TMD pain and pain-free subjects, as studied in this Validation Project, but also, more importantly, how they discriminate between patients with TMD pain and patients with oro-facial pain (OFP) complaints of non-TMD origin. We welcome the suggestion of an international expert panel to consider, deliberate, and reach consensus on a revised version of the RDC/TMD. Finally, we agree that the suggested expansions of the RDC/TMD taxonomy stress the need for the development of an RDC for OFP, which would include, as an integral part, the revised RDC/TMD.

Effects of intense chewing exercises on the masticatory sensory-motor system.

Nociceptive substances, injected into the masseter muscle, induce pain and facilitate the jaw-stretch reflex. It is hypothesized that intense chewing would provoke similar effects. Fourteen men performed 20 bouts of 5-minute chewing. After each bout, 20 min and 24 hrs after the exercise, muscle fatigue and pain scores and the normalized reflex amplitude from the left masseter muscle were recorded. Before, 20 min, and 24 hrs after the exercise, signs of temporomandibular disorders and pressure-pain thresholds of the masticatory muscles were also recorded. Fatigue and pain scores had increased during the exercise (P < 0.001), but the reflex amplitude did not (P = 0.123). Twenty minutes after the exercises, 12 participants showed signs of myofascial pain or arthralgia. Pressure-pain thresholds were decreased after 20 min (P = 0.009) and 24 hrs (P = 0.049). Intense chewing can induce fatigue, pain, and decreased pressure-pain thresholds in the masticatory muscles, without concomitant changes in the jaw-stretch reflex amplitude.

[Myogenous temporomandibular pain: treat with care!]. / Myogene temporomandibulaire pijn: behandelen met aandacht!

For the treatment of myogenous temporomandibular pain, a clinician can choose from among a wide variety of possibilities. Unfortunately, a paper summarizing the effectiveness of all these forms of treatment does not yet exist. The aim of this paper is to provide specific advice for dentists concerning the treatment of patients with myogenous temporomandibular pain by means of a systematic review of the relevant literature. The results of this review of the literature suggest that all forms of treatment selected, including treatment with placeboes, are equally effective in reducing myogenous temporomandibular pain. In order to avoid liability issues, it is advisable to choose for a restrained, reversible form of treatment. The dentist and the patient must, in this respect, be aware that the pain can continue after treatment (albeit at a reduced level) or can return after a period of time.

Reliability and validity of the instrumental assessment of implant stability in dry human mandibles.

The aim of this study was to determine the intra- and interobserver reliability and validity of the instrumental assessment of primary dental implant stability, using resonance frequency analysis (RFA). Sixteen tapered implants and 16 cylindrical implants were installed in eight unfixed dry human mandibles (Cawood classification IV/V). Implant stability quotients (ISQ; the outcome variable of RFA) and peak removal torque were determined. Both the intra-observer reliability and the interobserver reliability of the RFA measurements were fair-to-good, while no significant correlations between the ISQ values and removal torque were found. The removal torque of the cylindrical implants was higher than that of the tapered implants. The smallest detectable difference was almost nine ISQ units. Within the limitations of the present dry cadaver study, it was concluded that (i) primary dental implant stability can be assessed reliably with RFA measurements, (ii) the concurrent validity between RFA measurements and removal torque is poor, (iii) cylindrical implants may be more stable than tapered ones and (iv) two subsequent readings of RFA measurements need to differ at least nine ISQ units before the difference between the two measurements can be considered statistically significant. More research is needed to see whether these conclusions can be extrapolated to the clinical situation, including the assessment of implants during function (secondary stability).

Time-variant nature of sleep bruxism outcome variables using ambulatory polysomnography: implications for recognition and therapy evaluation.

The aim of this study was to quantify the time-variant nature of sleep bruxism (SB) and to discuss its consequences. Six clinically diagnosed bruxers and six non-bruxers participated. Four ambulatory polysomnographic (PSG) recordings were obtained for every participant. As SB outcome variables, the number of episodes per hour of sleep (Epi h(-1)), the number of bursts per hour (Bur h(-1)) and the bruxism time index (BTI: the percentage of total sleep time spent bruxing) were established. To quantify the time-variant nature of SB, standard errors of measurement (SEMs) were calculated. For the non-bruxers, the SEMs for Epi h(-1), Bur h(-1) and BTI were 1.0, 5.7 and 0.1. For the bruxers, the respective values were 2.1, 14.9 and 0.4. In the discussion, arguments are given that because of the time-variant nature of the PSG recordings, cut-off bands around cut-off points might be useful for the recognition of SB.

Principles for the management of bruxism.

The management of bruxism has been the subject of a large number of studies. A PubMed search, using relevant MeSH terms, yielded a total of 177 papers that were published over the past 40 years. Of these papers, 135 were used for the present review. Apparently, research into bruxism management is sensitive to fashion. Interest in studying the role of occlusal interventions and oral splints in the treatment of bruxism remained more or less constant over the years: between 1966 and 2007, approximately 40-60% of the papers dealt with this subject. The percentage of papers that dealt with behavioural approaches, on the other hand, declined from >60% in the first 2 decades (1966-1986) to only slightly >10% in the most recent decade (1997-2007). In the latter period, >40% of the papers studied the role of various medicines in the treatment of bruxism, while in the preceding decade (1987-1996), only approximately 5% of the studies dealt with the pharmacological management of bruxism. Unfortunately, a vast majority of the 135 papers have a too low level of evidence. Only 13% of the studies used a randomized clinical trial design, and even these trials do not yet provide clinicians with strong, evidence-based recommendations for the treatment of bruxism. Hence, there is a vast need for well-designed studies. Clinicians should be aware of this striking paucity of evidence regarding management of bruxism.