The incidence and nature of fibrous continuity between the sphenomandibular ligament and the anterior malleolar ligament of the middle ear.

The purpose of this study was to determine the structural interrelationship between the temporomandibular joint (TMJ) and the middle ear, in terms of fibrous continuity between the sphenomandibular ligament (SML) of the mandible and the anterior malleolar ligament (AML) of the middle ear. Thirty-seven specimens of the TMJ and middle ear were obtained from adult human cadavers. The temporal bone, petrotympanic fissure, mandibular fossa, and middle ear were dissected en bloc, fixed, sectioned, stained, and observed microscopically. Of the 37 specimens, 67.6% had a continuity of the SML through the fissure passing near the malleus of the middle ear. The AML was present at the fissure in 64.9% of the specimens, with 58.3% passing through and not stopping at the fissure. Results indicated a fibrous continuity between the SML and the AML. Structural differences between the two ligaments were also noted. The SML contained randomly arranged fibrous connective tissue with numerous interposed blood vessels. The AML had a smooth arrangement of fibers within the connective tissue, and few blood vessels were apparent. The clear anatomic relationship observed strongly supports the contention of a functional interrelationship between the TMJ and the middle ear.

Effect of increased maxillo-mandibular relationship on isometric strength in TMD patients with loss of vertical dimension of occlusion.

The effect on isometric strength of the shoulders and limbs while biting in habitual occlusion, on a bite-elevating appliance and on a placebo appliance was analyzed. Twenty female volunteer patients, presenting with temporomandibular pain dysfunction syndrome and obvious loss of vertical dimension, served as subjects. All were weaker to the manual application of the isometric Deltoid Press (IDP) when biting, as opposed to maintaining the mandible in an unsupported rest position. Two intraoral appliances were fabricated for each subject: a bite-elevating appliance (BEA) set by a functional criterion of peak strength to the IDP and a placebo appliance which did not interfere with occlusion but was "set" with a mock IDP procedure. Testing was carried out by the Neuromuscular Research Testing Laboratory of the Neurology Department of Tufts New England Medical Center. Testing was independent of the dentist who fabricated and set the appliances. A standard neuromuscular test with the Maximal Voluntary Isometric Contraction apparatus was used to assess strength of right and left shoulder, elbow and knee flexion and extension as is routinely performed with all neuromuscular disease patients. Twelve strength tests were carried out for each of three conditions: 1. Baseline-biting in habitual occlusion; 2. Elevated-biting on the BEA; and 3. Placebo-biting with the placebo appliance inserted. The order of conditions 2 and 3 was counterbalanced without knowledge of the subjects. Twelve repeated measures ANOVAs (each subject as their own control) were conducted for each of the 12 strength measures. All F-tests indicated a significant main effect for treatment differences (p < 0.0001). Mean strength biting on the BEA was consistantly greater (p < 0.001) than Baseline or Placebo strength. Baseline and Placebo condition were equivalent. These findings confirmed previous observations at this TMD Center: individuals with loss of vertical dimension of occlusion respond to a bite raising appliance by increased isometric-strength.

Anatomic basis for disk displacement in temporomandibular joint (TMJ) dysfunction.

This study was designed to investigate the site of lateral pterygoid muscle insertion into the temporomandibular joint (TMJ) disk, and the relationship between that attachment and the disk displacement. One hundred and ten TM joints from 78 cadavers were collected and sectioned in the sagittal plane. Sixty-two unilateral specimens were available and 16 additional specimens were selected randomly from the remaining cadavers in which both condyles were available. Thus statistical comparisons were not confounded by autocorrelation and were based on 78 independent specimens. The sites of muscle attachment in relation to the disk were identified histologically. Of the 78 joints 49 had anterior disk displacement. Of the 42 cases with insertion directly into the disk, 30 had anterior disk displacement. In contrast, only 19 of the 36 disks without direct muscle insertion were displaced. This finding indicated a statistically significant relationship between functional muscle attachment and disk displacement (chi 2 = 9.28, df = 1, p = 0.006). However, the superior head of the lateral pterygoid muscle (SLP) may not be the precipitating factor for anterior disk displacement even though it does coordinate disk movement on closure. Since other factors (e.g., trauma) can result in disk displacement, the SLP can maintain disk displacement only when it inserts directly into the disk. In cases of normal disk arrangement and condylar attachment, the muscle may not play a clinically significant role in disk displacement because disk attachment at the medial and lateral poles of the condyle allows the disk to move freely with the condyle.(ABSTRACT TRUNCATED AT 250 WORDS)

The sublingual crescent extension and its relation to the stability and retention of mandibular complete dentures.

The extension of the flange in the sublingual crescent region is an important factor for mandibular denture stability and retention. Making the impression with minimal pressure on the floor of the mouth while the tongue is at rest allows greater mobility of the underlying muscles without denture dislodgment and without occlusion of the sublingual gland ducts. The anatomy of the sublingual crescent region and the clinical procedure for recording the anterior lingual seal region are described. Upon completion of the impression, resistance to dislodgment is usually achieved.

Bursitis of the tensor veli palatini muscle with an osteophyte on the pterygoid hamulus.

Many patients with temporomandibular joint dysfunction and/or myofascial pain syndrome have numerous symptoms. In cases of multiple complaints, an attempt should be made to resolve symptoms on a step-by-step basis. In this case report, a patient was treated for only one of her numerous complaints, that is, a burning sensation on her palate when she touched the right tuberosity area with her tongue or finger.

Dentinal bonding after chemomechanical caries removal--effect of surface topography.

A study was carried out to determine whether or not the topography of the dentinal surface that is left after caries removal affects bond strength. The caries was removed either by a rotating instrument and a bur or by the chemomechanical method using D,L,2-aminobutyric acid. The bond strength appeared to be enhanced on those specimens treated by the chemomechanical removal since the surface was characterized by lack of a smeared layer and by open dentinal tubules and numerous undercuts.

Porion and condyle as cephalometric landmarks--an error study.

With the recent increase in the use of functional appliances for orthodontic treatment in which condylar growth plays an important role in the final results, orthodontists and researchers should be aware of the process of growth and development of various components of the skull to see the changes of measurements on cephalometric tracings in different stages of treatment. This study was conducted to assess the reliability of the porion and condyle on the lateral cephalogram. A group of 24 patients was selected randomly from the Orthodontic Department at Tufts University. Two sagittal roentgenograms, one in habitual (centric) occlusion and one with the mouth wide open, were taken. Each cephalogram was traced by two observers to determine discrepancies in tracing the shape and position of the porion and condyle. The Pearson product-moment coefficient of correlation was performed for inter- and intraobserver reliability for locating the porion and condyle in open- and closed-mouth positions. It was concluded that the porion and condyle cannot be located accurately and consistently on sagittal roentgenograms in the closed-mouth position. Therefore it appears advisable to obtain an open-mouth cephalogram and superimpose it onto the respective closed-mouth cephalogram. This will provide greater accuracy and reliability in obtaining cephalometric measurements.

The relationship between patency of the maxillary sinus and craniofacial growth in the rabbit.

Numerous researchers report the interaction between deviant respiratory patterns (airway obstruction) and craniofacial growth. Many of these studies consisted of cephalometric evaluations of children with enlarged adenoids, obstruction turbinates, or other nasal obstructions. Other experimental studies of the airway's influence on growth include studies that have induced nasal obstruction in animals by plugging the external nares. No investigations were found that examined the role of the paranasal sinuses in craniofacial growth by filling a sinus in growing animals. Furthermore, nothing appears in the literature that considers the paranasal sinuses in the oronasopharyngeal functional matrix theory. The purpose of this study was twofold: (1) to determine the effect of decreasing the pneumatization of the maxillary sinus on ultimate craniofacial growth and development, and (2) to determine the effect on future morphology by obturating a growing sinus. New Zealand white weaning rabbits were used as the experimental animals. Unilateral maxillary sinuses were injected in 18 animals--nine animals were injected on the right side and nine on the left. Eight rabbits served as controls: five received left-side and three right-side sham injections. Dorsal view cephalometric radiographs were taken at (1) the start, (2) at three progress intervals, and (3) at the end of the experiment. Dried skull direct measurements also were performed at the conclusion of the experiment. No statistical significance was found when comparing right and left sides within groups or when comparing any measurement between groups. This demonstrated that filling the maxillary sinuses had no effect on craniofacial growth; the sinuses grew normally in all animals.

Statistical evaluation of the position of the mandibular foramen.

The position of the mandibular foramen and its importance to successful inferior alveolar anesthesia has been well documented. The current study attempts to use position of the narrowest AP width of the ramus and the gonial angle as the important parameters in locating MF, rather than using isolated measurements of the bony mandible proper.

Reflex vasoconstriction following dental injections.

Three case reports of transient facial blanching or vasoconstriction that followed administration of dental anesthetic are presented. A review of vasomotor cutaneous control is given, along with a proposal to explain this phenomenon.

The coronomaxillary space: literature review and anatomic description.

The dental literature has used a variety of terms to describe the distal buccal boundaries of the maxillae. The coronomaxillary space has been suggested as a more consistent descriptive term. It has been noted in the literature that this space narrows on mandibular opening. However, some authors recommend that overfilling this space aids retention. Explanations for this seeming contradiction in opinions have been suggested: In individuals with straight coronoid processes, the space can narrow on opening. The coronomaxillary denture may have to be thinned to maintain retention in function. In individuals with flared coronoid processes, the space can widen or remain constant on opening. The denture borders may have to be widened in contour to achieve retention.

Referral of symptoms from the trigeminal to the facial nerve as a sequel to dental infection.

The case reported in this article documents a clinical situation in which an infected tooth resulted in secondary clinical manifestations involving the seventh cranial nerve in addition to the fifth cranial nerve. A theory for the referral mechanism is proposed.

Flushing of the face as a result of chewing food.

This case depicts a clinical situation in which the patient's face became flushed after chewing food for approximately 30 seconds. The distribution of the flushing accurately defines the distribution of the zygomaticofacial branch of the trigeminal nerve. A theory involving the parasympathetic supply to this area is presented to explain this clinical pattern.

Orofacial involvement secondary to trapezius muscle trauma.

The case reported in this article demonstrates an unusual referral mechanism for signs and symptoms of the face and the oral cavity emanating from a traumatized trapezius muscle. A theory for this referral, based on central connections of nerves V, VII, IX, X, and XI, is proposed.

Class II, division 1 treatment with Fränkel and Edgewise appliances--a comparative study of mandibular growth and facial esthetics.

A statistical comparison of treatment changes in twenty patients treated with a Fränkel appliance and twenty treated with the Edgewise mechanism. Both groups showed similar improvements, with no significant differences in mandibular growth.

The neuronal basis for diplopia following local anesthetic injections.

The case report presented here describes a situation in which diplopia resulted as an effect secondary to maxillary infiltration anesthesia. Prior cases and theories regarding the mechanisms involved are reviewed, and a new theory explaining this phenomenon is proposed. The autonomic nervous system is presented as the logical basis for the untoward systems, rather than simple circulation of anesthetic solution in the vascular tree.