Standardised Tool for the Assessment of Bruxism.

OBJECTIVE: This paper aims to present and describe the Standardised Tool for the Assessment of Bruxism (STAB), an instrument that was developed to provide a multidimensional evaluation of bruxism status, comorbid conditions, aetiology and consequences. METHODS: The rationale for creating the tool and the road map that led to the selection of items included in the STAB has been discussed in previous publications. RESULTS: The tool consists of two axes, specifically dedicated to the evaluation of bruxism status and consequences (Axis A) and of bruxism risk and etiological factors and comorbid conditions (Axis B). The tool includes 14 domains, accounting for a total of 66 items. Axis A includes the self-reported information on bruxism status and possible consequences (subject-based report) together with the clinical (examiner report) and instrumental (technology report) assessment. The Subject-Based Assessment (SBA) includes domains on Sleep Bruxism (A1), Awake Bruxism (A2) and Patient's Complaints (A3), with information based on patients' self-report. The Clinically Based Assessment (CBA) includes domains on Joints and Muscles (A4), Intra- and Extra-Oral Tissues (A5) and Teeth and Restorations (A6), based on information collected by an examiner. The Instrumentally Based Assessment (IBA) includes domains on Sleep Bruxism (A7), Awake Bruxism (A8) and the use of Additional Instruments (A9), based on the information gathered with the use of technological devices. Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid association with bruxism. It includes domains on Psychosocial Assessment (B1), Concurrent Sleep-related Conditions Assessment (B2), Concurrent Non-Sleep Conditions Assessment (B3), Prescribed Medications and Use of Substances Assessment (B4) and Additional Factors Assessment (B5). As a rule, whenever possible, existing instruments, either in full or partial form (i.e. specific subscales), are included. A user's guide for scoring the different items is also provided to ease administration. CONCLUSIONS: The instrument is now ready for on-field testing and further refinement. It can be anticipated that it will help in collecting data on bruxism in such a comprehensive way to have an impact on several clinical and research fields.

The development of the Standardised Tool for the Assessment of Bruxism (STAB): An international road map.

This paper summarises the background reasoning and work that led to the selection of the items included in the Standardised Tool for the Assessment of Bruxism (STAB), also introducing the list of items. The instrument is currently being tested for face validity and on-field comprehension. The underlying premise is that the different motor activities included in the bruxism spectrum (e.g. clenching vs. grinding, with or without teeth contact) potentially need to be discriminated from each other, based on their purportedly different aetiology, comorbidities and potential consequences. Focus should be on a valid impression of the activities' frequency, intensity and duration. The methods that can be used for the above purposes can be grouped into strategies that collect information from the patient's history (subject-based), from the clinical assessment performed by an examiner (clinically based) or from the use of instruments to measure certain outcomes (instrumentally based). The three strategies can apply to all aspects of bruxism (i.e. status, comorbid conditions, aetiology and consequences). The STAB will help gathering information on many aspects, factors and conditions that are currently poorly investigated in the field of bruxism. To this purpose, it is divided into two axes. Axis A includes the self-reported information on bruxism status and potential consequences (subject-based report) together with the clinical (examiner report) and instrumental assessment (technology report). Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid role for bruxism. This comprehensive multidimensional assessment system will allow building predictive model for clinical and research purposes.

Digital versus conventional complete dentures: A randomized, controlled, double-blinded crossover trial.

STATEMENT OF PROBLEM: The Baltic Denture System provides a digital way to fabricate complete dentures in 2 visits. Conventional dentures using injection or compression molding require additional visits and complex laboratory procedures. However, how the fabrication method affects clinical outcomes is unclear. PURPOSE: The purpose of this clinical, randomized, controlled, double-blinded crossover trial was to evaluate the impact of the fabrication method (digital versus conventional production) of complete dentures on clinical outcomes. MATERIAL AND METHODS: Sixteen participants received 2 pairs of new complete dentures, produced in a digital and a conventional workflow. Each complete denture was worn for an observation period of 3 months. The order of the dentures was randomized. The primary outcome was the clinical assessment of the dentures by a blinded examiner, including peripheral extension, cutout for buccal and labial frenula, denture extension, and denture thickness. Denture esthetics were evaluated by the midline, position of anterior teeth, buccal corridor, and smile arc, and occlusal relationships were evaluated by the vertical dimension, sagittal relation, the Camper plane, and occlusion. In addition, the retention of maxillary and mandibular dentures and phonetics was evaluated. Differences between the prostheses were statistically analyzed with the McNemar test (α=.05). RESULTS: The borders of the digital dentures were significantly more often overextended at the time of insertion (P=.021), reducing the retention of the digital dentures, especially the maxillary dentures (P=.016). The borders of the dentures could be corrected so that after 2 weeks and 3 months, no significant differences could be seen between digital dentures and conventional dentures. CONCLUSIONS: The fabrication method has a significant influence only on the dimension of the denture border. It was significantly more often overextended in digital dentures and impaired retention, especially of the maxillary dentures, at the time of insertion. As this parameter is correctable, no significant clinical differences could be observed over the observation time of 3 months between digital dentures and conventional dentures.

Digital versus conventional complete dentures: A randomized, controlled, blinded study.

STATEMENT OF PROBLEM: Several manufacturers have developed a digital workflow for removable prosthodontics. The Baltic Denture System is a 2-visit procedure for the digital production of complete dentures, but clinical studies comparing the system with conventional methods are lacking. PURPOSE: The purpose of this randomized, controlled, blinded crossover trial was to evaluate the impact of the digital versus conventional production of complete dentures on oral health-related quality of life (OHRQoL) measures. MATERIAL AND METHODS: Sixteen participants received 2 sets of new complete dentures produced with a digital (2 visits) and conventional (5 visits) workflow. Each complete denture was in clinical service for an observation period of 3 months. The order of the dentures was randomized, starting with digital or conventional followed by changing the set of dentures after 3 months. The primary outcome was the time-dependent change in the OHRQoL, assessed by using the Oral Health Impact Profile, German version (OHIP-G49), comparing the digital with the conventional workflow. The secondary outcome was the time needed for the fabrication process. The median values of OHIP-G49 total sum scores and OHIP-G49 dimensions were calculated for baseline and 14 days and 3 months after insertion of the dentures. Changes of sum scores over time and differences between the workflows were analyzed by using the Wilcoxon signed-rank test (α=.05). RESULTS: The data of 16 participants (11 men and 5 women; 66 ±8.5 years) were evaluated. The median values of the total OHIP-G49 sum scores and the sum scores of OHIP-G49 dimensions did not differ between workflows (P>.05). With digital dentures, more physical pain was observed after 2 weeks (P=.039). Participants with conventional dentures had less functional limitation after 14 days and felt less handicapped after 3 months (P=.036). Digital dentures were fabricated within 4 hours, whereas fabrication of conventional dentures took 10.5 hours for dentists and dental laboratory technicians. CONCLUSIONS: From the perspective of the participants, the fabrication method of the complete dentures had no significant influence on OHRQoL. However, digital dentures needed only 2 visits, 1 hour less chair time, and 5 hours less time for the dental laboratory technicians.

Marginal adaptation of lithium disilicate ceramic crowns cemented with three different resin cements.

OBJECTIVES: The cementation process and cementation materials have an influence on the marginal adaptation of restorations. The gap could be affected by thermal and mechanical loading (TCML). The computerized x-ray microtomography (µCT) method offers the possibility of measuring the marginal gap without destruction of the restoration. The aim of this study was to evaluate the marginal gap (MG) and the absolute marginal discrepancy (AMD) before and after TCML. MATERIALS AND METHODS: Thirty-nine human premolars were prepared for full ceramic crowns made of lithium disilicate. The crowns were cemented by three different resins-Panavia F 2.0, Variolink II, and Relyx Unicem. The MG and AMD were evaluated by µCT before and after TCML. RESULTS: Panavia F 2.0 had the lowest MG (before 118 µm-after TMCL 124 µm) and AMD (before 145 µm-after TMCL 154 µm), followed by Relyx Unicem (MG: before 164 µm-after TCML 155 µm; AMD: before 213 µm-after TMCL 209 µm) and Variolink II (MG: before 317 µm-after TMCL 320 µm; AMD: before 412 µm-after TMCL 406 µm). The differences were statistically significant before and after TCML. Rather than TCML, it appeared the resin cement was responsible for differences between the MG and AMD before and after TCML. CONCLUSIONS: µCT is an accurate technique for assessing cemented restorations. Panavia F 2.0 has the lowest MG and AMD before and after TCML. CLINICAL RELEVANCE: The resin material that features a three-step protocol (Variolink II) produced higher MG and AMG values than the Panavia or Relyx Unicem varieties with less or no intermediate steps at all.

Influence of a face-bow on oral health-related quality of life after changing the vertical dimension in the articulator: a randomized controlled trial. Part II.

OBJECTIVES: In a double-blind randomized controlled clinical trial, the impact of face-bow registration for remounting complete dentures (CDs) on oral health-related quality of life (OHRQoL) was evaluated. MATERIALS AND METHODS: New CDs of 32 subjects were clinically remounted using intraoral pin registration. CDs were transferred into a semi-adjustable articulator corresponding to group #1: mean settings with Bonwill triangle and Balkwill angle, and group #2: arbitrary hinge axis with a face-bow registration. After occlusal adjustment, subjects were followed up after 3 (T1) and 84 (T2) days. The primary outcome was the change of OHRQoL by OHIP-G49, while as secondary outcome, mucosal alterations were evaluated over time. Mean values of OHIP-G49 total sum scores and OHIP-dimensions were calculated for baseline (T0) and days 3 (T1) and 84 (T2) after intervention. Based on bootstrapping methods (changes of total OHIP sum score) and the Wilcoxon test (changes of sum scores of OHIP dimensions), analyses of between-group differences were performed. RESULTS: Mean values (MV) of OHIP-G49 sum scores decreased in both groups from T0 (#1 48.56; #2 45.46) to T1 (#1 31.43 (p = 0.012); #2 43.20) and to T2 (#1 29.06; #2 29.40), which represents an improvement in OHRQoL. MV of OHIP-dimension sum scores decreased from T0 to T1 in both groups (#1 seven dimensions; #2 four dimensions); the decrease of sum scores was tested as not statistically significant (p > 0.05). CONCLUSIONS: From the patient's perspective, mean-value-based remounting methods are of value. The use of a face-bow was not perceived as superior. CLINICAL RELEVANCE: From the patient's perspective, remounting of CDs will be positively perceived, irrespective of the use of a face-bow.

Does a face-bow lead to better occlusion in complete dentures? A randomized controlled trial: part I.

OBJECTIVES: In a double-blinded randomized controlled clinical trial, the impact of face-bow registration for remounting complete dentures (CDs) on the occlusal parameters (part I) was evaluated. MATERIALS AND METHODS: New CDs of 32 patients were duplicated and mounted after intraoral pin registration according to mean settings (group 1) and (group 2) using a face-bow (arbitrary hinge axis). The vertical dimension was reduced to the first occlusal contact point, and a bite record was fabricated in the articulator. The number of contacts and the number of teeth in contact were evaluated by a computer program (laboratory result). After randomization, half of the CDs were adjusted according to protocol of group 1 and group 2 and delivered to the patients. After 3 days (T1) and 84 days (T2), clinical static contact points and teeth in contact were counted. Contact points and teeth in contact of both groups (laboratory results) and at different moments (clinical results) were analyzed statistically with the F test and bootstrapping. RESULTS: Laboratory: No. 2 (face-bow) showed more occlusal contact points than no. 1 (mean setting), p > 0.05. The number of teeth with at least one occlusal contact was significantly higher in no. 2 (p = 0.027). Clinic: The mean number of teeth with at least one clinical contact point was significantly higher in no. 1 (no. 1 = 7.13, no. 2 = 5.31; p = 0.042). Extent of the vertical shift poorly correlated with number of laboratory occlusal contact points (R 2 = 0.017). CONCLUSIONS: Considering the complex multistep study design, a limited number of participants, and referring to one specific arbitrary face-bow, the following conclusion could be drawn: no substantial difference by the use of the arbitrary face-bow compared to a mean setting could be determined, when changing the vertical dimension in the articulator within a remounting procedure of complete dentures. CLINICAL RELEVANCE: Further research is necessary to determine the effects of different arbitrary face-bows on the fabrication and adaptation of removable dentures.

A multidisciplinary systematic review of the treatment for chronic idiopathic tinnitus.

The majority of tinnitus patients are affected by chronic idiopathic tinnitus, and almost 60 different treatment modalities have been reported. The present study is a multidisciplinary systematic analysis of the evidence for the different forms of treatment for chronic tinnitus. The results are used to form the basis of an S3 guideline. A systematic search was carried out in PubMed and the Cochrane Library. The basis for presenting the level of evidence was the evidence classification of the Oxford Centre of Evidence-based Medicine. Whenever available, randomised controlled trials were given preference for discussing therapeutic issues. All systematic reviews and meta-analyses were assessed for their methodological quality, and effect size was taken into account. As the need for patient counselling is self-evident, specific tinnitus counselling should be performed. Due to the high level of evidence, validated tinnitus-specific, cognitive behavioural therapy is strongly recommended. In addition, auditory therapeutic measures can be recommended for the treatment of concomitant hearing loss and comorbidities; those should also be treated with drugs whenever appropriate. In particular, depression should be treated, with pharmacological support if necessary. If needed, psychiatric treatment should also be given on a case-by-case basis. With simultaneous deafness or hearing loss bordering on deafness, a CI can also be indicated. For auditory therapeutic measures, transcranial magnetic or direct current stimulation and specific forms of acoustic stimulation (noiser/masker, retraining therapy, music, and coordinated reset) for the treatment of chronic tinnitus the currently available evidence is not yet sufficient for supporting their recommendation.

Comparison of effects of OSA treatment by MAD and by CPAP on cardiac autonomic function during daytime.

PURPOSE: The present study compared the effects of mandibular advancement therapy (MAD) with continuous positive airway pressure therapy (CPAP) on daytime cardiac autonomic modulation in a wide range of obstructive sleep apnea (OSA) patients under controlled conditions in a randomized, two-period crossover trial. METHODS: Forty OSA patients underwent treatment with MAD and with CPAP for 12 weeks each. At baseline and after each treatment period, patients were assessed by polysomnography as well as by a daytime cardiac autonomic function test that measured heart rate variability (HRV), continuous blood pressure (BP), and baroreceptor sensitivity (BRS) under conditions of spontaneous breathing, with breathing at 6, 12, and 15/min. RESULTS: Both CPAP and MAD therapy substantially eliminated apneas and hypopneas. CPAP had a greater effect. During daytime with all four conditions of controlled breathing, three-minute mean values of continuous diastolic BP were significantly reduced for both MAD and CPAP therapy. At the same time, selective increases due to therapy with MAD were found for HRV high frequency (HF) values. No changes were observed for BRS in either therapy mode. CONCLUSIONS: These findings indicate that both MAD and CPAP result in similar beneficial changes in cardiac autonomic function during daytime, especially in blood pressure. CPAP is more effective than MAD in eliminating respiratory events.

Electronic central bearing point as registration method in individuals with and without temporomandibular disorders.

OBJECTIVES: The aim of this study was to examine different central bearing point methods in patients with and without temporomandibular disorders (TMD) by an experienced and unexperienced examiner. MATERIAL AND METHODS: The 20 fully dentulous subjects were screened for TMD based on the Research Diagnostic Criteria for TMD and distinguished into functional impaired and functional healthy groups. The mandibular relationship was recorded by an electronic central bearing tracing device (IPR-System, IPR GmbH, Oldenburg, Germany) with an integrated pressure sensor. Three bite registration methods were performed using this device: initial neuromuscular position, final neuromuscular position after dynamic sequences with the intraoral pin (=neuromuscular deprogramming), and centric relation guided manually by an experienced and an unexperienced examiner. RESULTS: The neuromuscular positions before and after neuromuscular deprogramming were not significantly different (paired t test as a group comparison test: transverse: p = 0.369; sagittal: p = 0.486). Both positions were significantly anterior in comparison to the manually guided centric relation (paired t test as a group comparison test: p < 0.0001). The neuromuscular positions before and after deprogramming tend to have high scattering values. CONCLUSION: By means of the central bearing point method, the manually guided centric relation is the one which is sufficiently reproducible. It seems doubtful to take the significant anterior neuromuscular position for a definite reconstruction. CLINICAL RELEVANCE: Using the central bearing point method, the manually guided centric relation should be preferred, whereas the neuromuscular position should not be used for definite reconstructions.

Fiber post placement with core build-up materials or resin cements-an evaluation of different adhesive approaches.

OBJECTIVE: To compare push-out bond strength of fiber-posts luted with different adhesive approaches to root canal dentin. MATERIALS AND METHODS: Forty maxillary first incisors were decoronated and endodontically treated. Specimens were randomly distributed into five groups (n = 8) and fiber-posts (DentinPost coated, Komet) were inserted using five different luting materials: etch-and-rinse adhesive systems and corresponding core-and-post material in groups 1 (DentinBond/DentinBuild, Komet) and 2 (XP Bond + SCA/Core-X flow, Densply), self-adhesive resin cements in groups 3 (RelyX Unicem, 3M Espe) and 4 (SmartCem 2, Dentsply) and a self-etch adhesive/resin cement in group 5 (ED-Primer II/Panavia F 2.0, Kuraray). The roots were sectioned into eight 1 mm thick serial slices and within 48 h push-out bond strength was investigated. Statistical analyses were performed using non-parametrical Kruskal-Wallis H-test and Mann-Whitney U-test for differences between experimental groups at p < 0.05. The failure modes were analyzed using Chi square test. RESULTS: The bond strength [MPa] (mean/min-max) for groups 3 (12.35/3.60-32.44), 4 (13.52/4.48-30.69) and 2 (11.15/5.23-35.58) were significantly higher (p < 0.001) compared to groups 1 (6.66/2.34-24.89) and 5 (7.41/0.28-34.18). Adhesive failure between dentin and luting agent was the most frequent failure mode. CONCLUSIONS: Bond strength of fiber-posts adhesively luted to root canal dentin was significantly higher when self-adhesive resin cements were used. One (group 2) of the tested core-and-post materials/etch-and-rinse adhesive achieved comparable bond strength values.

Influence of professional dental hygiene on oral and general health of retirement home residents: A comparative study.

OBJECTIVES: The oral status of nursing home residents is poor. This could compromise general health. The controlled study investigated the influence of quarterly professional dental hygiene interventions on oral and general health of elderly. MATERIAL AND METHODS: 152 participants (mean age 84 years) of two residents' homes were examined. Parameters of general health, a questionnaire for caregivers, and oral parameters were evaluated at baseline and after 1 year. All caregivers were given one lesson on oral hygiene at baseline. In one home professional oral hygiene was performed every 3 months. Statistical analyses were done by Chi2 test for nominal data and t-test for numeric data. RESULTS: There were no significant differences between both homes regarding general health. Some oral parameters-if any-may be positively influenced by the intervention such as pocket depth, and Denture Hygiene Index and alterations of the mucosa. CONCLUSIONS: A quarterly professional hygiene is not able to influence general health and has-if any-little effect on oral health. This underlines the necessity for frequent interventions. An optimization of the health policy framework is necessary to allow caregivers more time for oral hygiene and to establish the accessibility of frequent professional health care for inhabitants in residents' homes.

[Stress, coping and craniomandibular disorders - a longitudinal study]. / Stress, Stressverarbeitung und kraniomandibuläre Dysfunktionen - eine Longitudinalstudie.

OBJECTIVES: Stress is widely accepted as an etiologic factor of craniomandibular disorders (CMD). There is, however, a lack of studies evaluating the significance of interindividual differences of stress and coping for the development of CMD. METHODS: 99 volunteers (33 male, 66 female) were observed over a period of 24 months. The clinical examination at the beginning and end of the observation time were carried out according to the protocol of the Research Diagnostic Criteria for Temporomandibular Disorders (Dworkin 1992). Data concerning stress and general body complaints were evaluated twice by questionnaires, and data on coping methods were collected at the beginning of the study. RESULTS: Stress, coping methods and general body complaints correlate with clinical functional parameters. Stress and body complaints proved to be significant predictors via linear regression analyses. CONCLUSIONS: Stress and general somatic complaints are predictors of the development of craniomandibular disorders.

Randomized controlled trial comparing lecture versus self studying by an online tool.

OBJECTIVES: Since 2001, an e-learning tool has been developed for dentistry. To compare online self study with traditional lectures, a module about instrumental occlusal analysis was offered by oral lecture and by a unit in the virtual library of the e-learning tool. METHODS: 85 pre-clinical dental students were randomly divided into two groups: the computer assisted learning (CAL) group (n = 48) and the lecture group (n = 37). A pre-test was made to assess the students' basic knowledge. The first post-test and the scoring of the teaching methods were performed immediately after the lecture or the self studying by the online tool and a second post-test six weeks later. RESULTS: The oral lecture got better educational and enjoyment values. The students prefer CAL in addition to traditional lectures. The results of the pre-tests were not different between the two groups (p = 0.706). The lecture group significantly improved their scores in the first post-test (p = 0.011), but the scores of the second post-test did not differ significantly (p = 0.157). CONCLUSIONS: In the short term, knowledge acquisition seems to be better in oral lectures but in the long term there is no difference in knowledge retention between the two learning scenarios.

Restoring endodontically treated teeth with posts and cores--a review.

OBJECTIVE: The prognosis of endodontically treated teeth depends not only on the success of the endodontic treatment, but also on the type of reconstruction. These considerations include the decision of whether or not to use posts. METHODS AND MATERIALS: A literature review has been performed to create guidelines for the reconstruction of endodontically treated teeth by posts and cores. RESULTS: Posts should only be used for the retention of core material in cases where little dental substance remains, ie, one or no cavity walls. A ferrule of 2 mm has to be provided, by surgical means if necessary. The post length is limited by the necessary apical seal of 4 to 6 mm. In cases of short posts, adhesive fixation is preferred. Ceramic posts show a higher risk of fracture than fiber posts which are retrievable. Composites have proven to be a good core material. Posts should be inserted if endodontically treated teeth are used as abutments for removable partial dentures. CONCLUSION: These guidelines are based mainly on in vitro studies with an evidence level of II a or II b, as there is a lack of randomized clinical studies available. The remaining tooth structure is an important factor influencing the indication of posts and cores, yet it is not sufficiently recognized in clinical studies and in vitro. Therefore, further prospective clinical studies are needed.

Comparison between balanced occlusion and canine guidance in complete denture wearers--a clinical, randomized trial.

OBJECTIVE: Two occlusal concepts exist for the setup of complete dentures: canine guidance and balanced occlusion. These two schemes were studied in a randomized clinical trial of 22 patients. METHOD AND MATERIALS: Subjective data were collected using a visual analog scale that described the patients' satisfaction with the esthetic appearance, the ability to chew, the ability to speak, and denture retention. Objective data were collected on the number of denture ulcers, the number of occlusal contacts, and denture retention during eccentric movements. Statistic evaluation was performed with the Friedman test. RESULTS: Patients assessed canine-guided dentures to be significantly more satisfying in esthetic appearance, mandibular denture retention, and chewing ability. The ability to speak and the retention of maxillary dentures were not influenced by the occlusal concept in the patients' opinion, whereas the examiners found that maxillary canine-guided dentures lost retention more frequently during eccentric movements than balanced dentures. The objective inspection of mandibular denture retention underscores the patients' assessment, showing that the mandibular canine-guided dentures are much more stable during laterotrusive and protrusive movements. CONCLUSION: Canine guidance can be used successfully in complete denture treatment as it provides better mandibular denture retention, esthetic appearance, and chewing ability.

The effect of processing methods and acrylic resins on the accuracy of maxillary dentures and toothless denture bases: an in vitro study.

OBJECTIVE: To compare the dimensional changes of two autopolymerising denture base resins using three different processing techniques. METHOD AND MATERIALS: Sixty edentulous denture bases were made from the polymethylmethacrylates FuturaGen and PalaXpress. Ten bases were made from each resin using a manual injection technique (MI), a pneumatic injection technique (PI), and the fluid resin technique (F). Posterior palatal gap widths between casts and denture bases were measured. For an additional three-dimensional examination of occlusal changes, 10 maxillary dentures were made using FuturaGen/MI and 10 using PalaXpress/PI. Intermolar widths and changes in vertical dimension were determined. In all groups, measurements were taken after polymerization, after removal and repositioning, after polishing, and after storage in water for 1 and 3 weeks. Data were analyzed by using two-way ANOVA and Tukey test (P < .05). RESULTS: There were no differences in dimensional changes of FuturaGen and PalaXpress specimens. The pneumatic injection system produced significantly smaller posterior palatal gaps after storage in water for 3 weeks compared to the manual injection system (P < .0005) and the fluid resin technique (P = .003). The posterior gaps of dentures were ⋜ 0.04 mm and below the recommended depth for carving a posterior palatal seal (0.4 to 3.0 mm). CONCLUSION: The processing technique rather than the choice of the two resins seems to be the dominate variable with respect to dimensional changes.

MRI of the TMJ: morphometric comparison of asymptomatic volunteers and symptomatic patients.

OBJECTIVE: Morphologic and morphometric differences in the anatomy of the temporomandibular joint (TMJ) between asymptomatic volunteers and patients with temporomandibular disorders (TMDs) were evaluated using magnetic resonance imaging (MRI). METHOD AND MATERIALS: Forty volunteers were examined using a 1.5-T MRI and double surface coils. Both temporomandibular joints were imaged simultaneously; 78 joints could be evaluated. Each TMJ was examined in the intercuspal position in a parasagittal plane. Images were analyzed morphometrically and morphologically and compared to data retrospectively obtained from 91 age-matched patients. RESULTS: Considering the position of the disc morphologically, 66.7% of the volunteers had a normal disc position while 28.6% of the patients did. Anterior disc displacement with reduction was diagnosed in 33.3% of volunteers and 31.0% of the patients. Anterior disc displacement without reduction was found only in patients (19.2%). Comparison of morphometric data between patients and volunteers revealed shortening of the disc and a thickening in the intermedial part and the posterior band in patients. In patients, the disc presented anteriorly and the condyle was positioned superiorly and posteriorly in the mandibular fossa when compared to the volunteers. Therefore, the posterior and superior joint spaces were smaller in patients. Women showed disc displacement and combined morphometric changes in the TMJ structures significantly more often than men. CONCLUSION: A large variation of morphometric parameters in temporomandibular joints could be demonstrated. However, reduced disc length, thickening of the disc, narrowed interarticular superior and posterior distances, and a superior-posterior position of the condyle are more commonly associated with joint pathology.

Masticatory performance in patients with anterior disk displacement without reduction in comparison with symptom-free volunteers.

Masticatory function can be impaired by craniomandibular disorders. The aim of this study was to assess masticatory performance in patients with an anterior disc displacement (ADD) without reduction. In the experiments, 29 patients and 33 age- and gender-matched volunteers chewed artificial test food for 60 chewing strokes. The collected remains of the test food were filtered, dried, fractionated by a sieving procedure, and weighed. The particle size distribution was then described using a cumulative distribution function. Patients and controls were clinically examined, and patients were asked to complete a pain questionnaire. Comparison with controls, patients showed significantly reduced masticatory performance. Patients that had had a disorder longer than 3 yr tended to display less reduction of their masticatory performance. Neither the treatment methods used, nor restriction of daily life activities or pain intensity were significantly correlated with masticatory performance. Jaw mobility was significantly reduced in patients. More than half of the patients and none of the controls had joint noises and trigger points in the masticatory muscles. Pain was present, in particular, during chewing and maximal opening of the mouth. It was concluded that patients with ADD without reduction have a significantly reduced masticatory performance.