Pivot appliances - is there a distractive effect on the temporomandibular joint?

The purpose of this study was to investigate the distractive effect of posterior occlusal pivots on the temporomandibular joint. The study comprised 23 healthy subjects. None of them had a third molar and none of them had a missing tooth or showed tooth mobility. All subjects clenched (i) on 1 mm tin foil positioned between the teeth 17/47 and 27/37; (ii) on a stiff bite registration material of 1 mm thickness that prevented protrusion because of its bold occlusal relief. During clenching on the tin foil and on the protrusion preventing bite registration material, respectively, the vertical and horizontal condylar position was measured using a 6 d.f. ultrasonic motion analyser. Clenching with maximal force on the tin foil lead to a noticeable anterior downward directed movement of the condyle. Clenching on the protrusion preventing pivot, however, caused a statistically significant upward condylar movement of about 0.3 mm. These results indicate that occlusal pivots have no distractive effect on the temporomandibular joint but can lead to unwanted joint compression, if they are designed in a way that is preventing protrusion.

[Otalgia as a result of certain temporomandibular joint disorders]. / Otalgien als Folge bestimmter kraniomandibulärer Dysfunktionen.

INTRODUCTION: Different hypotheses of reasons for common incidence of temporomandibular disorders (TMD) and otalgia have been discussed. The hypothesis of this study was, that the high prevalence of otalgia in patients with TMD may result in part from pain in the M. masseter pars prof. or in the temporomandibular joint (TMJ) which, due to the close anatomic neighborhood, can feel like ear pain. MATERIAL AND METHODS: [corrected] We retrospectively analyzed the anamneses of 720 of our TMD-patients with regard to main treatment motivation: how many patients quoted "pain in the ear" as main treatment motivation and how many of them had no objective findings in the ear but muscle tenderness of the M. masseter prof. or objective findings in the TMJ. Using all pairwise multiple comparison procedures (Dunn's Method) we compared the frequency of muscle and joint findings in patients with ear complaints to two controls: Tinnituspatients and patients seeking orthodontic treatment. RESULTS: 51 of 720 patients quoted ear pain as main treatment motivation. 25 of them (49 %) had findings in the masseter muscle, 9 (18 %) in the joint and 15 (29 %) had findings in both the joint and the muscle. The frequency of findings in the controls was significantly (p < 0.001) lower. CONCLUSION: A significant fraction of patients seeking treatment due to pain in the ear have no findings in the ear, but in the TMJ and in the masseter muscle.

[Influence of botulinum toxin on myogenous facial pain]. / Beeinflussung muskulärer Gesichtsschmerzen durch Botulinumtoxin A.

OBJECTIVE: Can chronic pain of the masticatory muscles be positively affected by low dose injection of botulinum toxin (BTX-A)? METHODS: Twenty patients suffering chronic myofacial pain were questioned and examined after injection of 25-50 U Dysport into the affected muscles over a period of 8 weeks. RESULTS: Four weeks after injection of BTX-A patients reported a significant reduction of pain (p <0.001, paired t-test. Power of performed test with alpha 0.050:1.000). Then the pain remained constant over the next 4 weeks. Concurrently a significant increase of mandubular range of movement was observed (p <0,05, Wilcoxon signed rank test). CONCLUSIONS: Even though lacking placebo control the findings suggest that patients suffering chronic myofacial pain may benefit from injection of low dose BTX-A into the affected muscles.

Impact of posterior occlusal support on the condylar position.

The purpose of this study was to investigate condylar displacement related to the loss of posterior occlusal support. Each of 23 subjects received one occlusal adjusted splint that covered all teeth from the right to the left second mandibular molar. None of the subjects had a third molar and none of them had a missing tooth or showed tooth mobility. The splint was inserted and vertical and horizontal condylar position was measured by an ultrasonic motion analyser. The splint was then unilateraly shortened tooth-by-tooth up to the canine tooth and the measurement was repeated after each shortening. Cutting off the splint's second molar on one side lead to a slight ipsilateral cranial motion of the condyle if subjects clenched with maximum voluntary force. If the second and first molar were cut off, a noticeable cranial condylar movement of about 0.3 mm was observed even when teeth occluded with low force. These results suggest that loss of posterior occlusal support as it happens in routine oral rehabilitation leads to a noticeable cranial condyle movement during registration, even if the clenching force is low.

[The "Costen Syndrome" - Which Symptoms Suggest that the Patient may Benefit from Dental Therapy?]. / Das "Costen Syndrom" - welche Befunde lassen aus HNO-ärztlicher Sicht die Zusammenarbeit mit einem Zahnarzt sinnvoll erscheinen?

INTRODUCTION: Since the thirties the hypothesis of a direct connection between temporomandibular disorders (TMD) and tinnitus/otalgia has been discussed. The thesis of this possible connection is often named after one of the earliest and most vehement supporters as "Costen Syndrome". This review is aimed to elucidate the present state of the discussion from the Dentist's point of view. DIAGNOSIS/EPIDEMIOLOGY/THERAPY OF TMD: Diagnostic research criteria which define TMD are not standardized. Despite high prevalence and strong demand for treatment of TMD there is still a lack of a commonly accepted standard therapy and the potential benefit from a therapeutic point of view is still controversial. TMD AND TINNITUS/OTALGIA:: Concurrence of TMD and tinnitus by a common underlying cause is still unproven. By contrast a causal link between certain forms of TMD and otalgia is obvious. CONCLUSION: A lack of clear definitions and standards for the diagnosis of TMD is the main hinderance to prove a causal relationship especially between TMD otalgia. However patients seeking care for otalgia with no identifiable otologic cause may benefit from dental therapy. Therefore future studies should focus on well defined subgroups of TMD to investigate a link between otalgia/tinnitus and TMD.

Serotype distribution and secretory acid proteinase activity of Candida albicans isolated from the oral mucosa of patients with denture stomatitis.

Denture stomatitis is the most common form of oral Candida infection in humans. In the current study, the distribution of Candida albicans serotype A and B as well as the activity of the secreted acid proteinase were determined in clinical isolates from patients with denture stomatitis. It was found that 70% of individuals with clinical signs of denture stomatitis exhibited fungal growth, with C. albicans representing the most frequently isolated species (75%). Of the C. albicans isolates, 75% were serotype A and 25% were serotype B, representing a significant increase of serotype B compared to a control group of non-denture-wearing HIV-seronegative individuals with oral candidiasis, but no significant difference compared with isolates from HIV-seropositive patients, who also exhibited a high percentage of serotype B. The mean secretory acid proteinase activity of C. albicans isolates from denture stomatitis patients (2796 +/- 819 U/l) was statistically not different from the mean secretory acid proteinase activity in non-denture-wearing HIV-seronegative individuals (2324 +/- 1487 U/l). Both values were significantly lower than the mean secretory acid proteinase activity of C. albicans from HIV-seropositive individuals (4256 +/- 2372 U/l). No correlation exists between the C. albicans serotype and the amount of secreted acid proteinase, indicating that serotype and secretory acid proteinase expression are two independent pathogenetic factors in oral candidiasis. These results indicate that there seems to be strain selection for C. albicans serotype B in denture stomatitis. These results further indicate that increased secretion of the acid proteinase seems to be of pathogenetic significance in the candidiasis of HIV-seropositive patients but not in denture stomatitis. Nevertheless, the secretory acid proteinase is likely to be an important pathogenetic factor also in denture stomatitis, where an increased secretion of the acid proteinase may not be required because of decreased salivary flow and a low pH under the denture, which will result in a high enzymatic activity.

[The result of the needle point tracing in dependence of the clenching force and changed needle position in the transverse direction]. / Das Ergebnis der Stützstiftregistrierung in Abhängigkeit von Kraft und veränderter Stiftposition in der Transversalen.

The effect of the positioning of the needle in the horizontal plane and the applied clenching force on the result of the needle point tracing was investigated. The results show a strong influence of the applied clenching force. The results on the variation of the needle position leaded to the conclusion, that in the progress of the needle point tracing the lower jaw is balanced over the central bearing point.

[Experimental investigations about the influence of the gnathological force on the results of the tracing pin registration]. / Experimentelle Untersuchungen zum Einfluss der Registrierkraft auf das Ergebnis der Stützstiftregistrierung.

With the help of video- and computer techniques is investigated in what respect the forces operating in intraoral tracing pin registration have an influence on the mandibular movement at the sagittal plane. The results significantly show this dependence.

[Effect of clenching forces on the results of needle point tracing in the sagittal plane]. / Uber den Einfluss der Kieferschlusskraft auf das Ergebnis der Stützstiftregistrierung in der Sagittalen.

It was the purpose of this study to assess the influence of the applied clenching force and the positioning of the needle in the sagittal plane on the results of needle point tracings. The results show a direct influence of the applied force, whereas the influence of the position of the needle point showed great interindividual variations.

[Studies on the elastic deformation of skeleton palatal plates]. / Untersuchungen zur elastischen Deformierung skelettierter Gaumenplatten.

The elastic behavior of various types of Kennedy Class II/1 skeleton palatal plates with transversal connectors of varying widths has been the subject of this study. During function a permanent deformation is not to be expected. Theoretical considerations give rise to the assumption that the support axis is not the border between load-carrying and unloaded maxillary areas. This border is rather shifted towards a bounded saddle situation due to the deformation of the major and minor connectors depending on the forces of mastication and the shape of the plate. Relieving the denture base is not necessary to avoid rocking. Increasing the rigidity of the denture base results in a reduction of the loads placed on the saddle on the one hand, and in an increase in the forces of draw at the counterlateral bounded saddle on the other, which may cause dislodging of the entire denture.

[Electromyographic studies on the masticatory muscles after the preparation of terminal molars as denture abutments]. / Elektromyographische Untersuchungen an der Kaumuskulatur nach Präparation endständiger Molaren als Brückenpfeiler.

When the occlusal surfaces of terminal molars are ground off during bridge preparation, the occlusal support for the condyle of the affected side disappears and thus the intermaxillary distance declines. The effect of this process on the masticatory muscles was examined electromyographically in nine patients. It was found that the muscle activity especially in the m. temporalis is immediately reduced by 30 to 40%.

[Elementary electromyographic analysis and motion patterns of the myoglossus muscle]. / Elementare elektromyographische Analyse und Bewegungsmuster des M. myloglossus

In five fully dentulous and one edentulous patient, the m. myloglossus was examined by means of concentric needle electrodes and implanted wire electrodes. It was not possible to achieve absolute inertia with the conductors. The individual potentials of motoric units are bi- and triphasic. The duration was 3 to 5 msec, and the amplitude was 200 to 800 muvolt. The portion of polyphasic potentials is about 5%. With moderate innervation the discharge frequency is 2 to 8/sec. With maximum innervation, interference activity is observed. Kinetic studies showed that the m.myloglossus acts as typical antagonist in lateral tongue movements and as synergist when raising tongue and throat. From these findings conclusions may be drawn with regard to prosthetics.

[Studies on the functional effect of the M. mylohyoideus on the base construction of total prostheses]. / Untersuchungen über den funktionellen Einflubeta des M. mylohyoideus auf die Basisgestaltung unterer Totalprothesen

By means of anatomical examinations as well as radiograms and jaw models of probands the inclination angles of the fibers of the oral diaphragm inserting in the hyoid bone are determined in order to obtain information for shaping the lingual margins of complete lower dentures. The transition from these fibers to the fibers inserting in the median raphe of the mylohyoid muscle is about 6 to 9 mm before the tip of the alveolar tubercle in edentulous mandibles, and in the area between the roots of the second molars in dentulous lower jaws with normal position of molars. In this area the muscle has, in most cases, an angle of inclination between 30 and 40 degrees to the perpendicular plane. The inclination of the posterior fibers of the mylohyoid muscle is most frequently between 10 and 25 degrees. The difference in inclination is mainly due to the varying width of the muscular insertion in the hyoid bone.