Ira E. Klein

Comparison of the fidelity of radiographs of mandibular condyles made by different techniques.

Abstract The radiograph is an important aid in the diagnosis of temporomandibular joint problems. A marked difference of opinion exists in the interpretation of radiographs produced by various techniques. To establish some common basis for agreement, a study of the morphology of the condyle of the temporomandibular joint was undertaken. Temporomandibular joints of cadavers were radiographed and dissected. The dissections revealed a startling variation in the form of condyles and many instances of pathologic aberrations. Radiographs of the temporomandibular joints were made by three commonly used techniques to correlate the morphology of condyles with their radiographic appearance. All three techniques (Atco, Updegrave and Lindblom) failed to provide a meaningful depiction of the three-dimensional appearance of condyles with irregular forms. Tomography was used to obtain radiographic information of greater diagnostic value. The Polytome H machine uses a hypocycloidal (twisting, pretzel-like) movement to provide radiographs of predetermined sections of structures. All structures other than the thin section desired are blurred out by the hypocycloidal movement of the machine. Tomographs were made of patients with temporomandibular joint problems in conjunction with conventional radiographs for diagnostic study and comparative evaluation. The tomographs provided evidence of condyle and glenoid fossa irregularities that were undetectable by the usual radiographs. When tomographs are made of both sides and in the open and closed positions, valuable clinical information about intercondylar symmetry and the comparative symmetry of condylar movement is provided. Tomography was used on cadavers to determine the fidelity of (1) conventional radiographs and (2) tomographic radiographs in relation to the gross structures they are expected to depict. Comparisons were made of radiographs of the in situ condyles that were obtained by the three one-plane techniques. No significant differences were observed in the radiographs obtained. Comparisons were made of in situ one-plane radiographs with the ideally angulated radiographs of the enucleated condyle. A fair degree of fidelity of the in situ radiographs was observed. However, both radiographs depicted only maximum contours of the condyle and failed to reveal irregularities in contour when asymmetry or pathologic aberrations are present. Comparisons were made of in situ one-plane radiographs with ideally angulated radiographs of the serial cuts of the enucleated condyle. Some degree of fidelity of the in situ radiographs was observed when a symmetrical condyle was sectioned. Lack of fidelity was noted when condylar irregularity was present. Comparisons were made of individual radiographs of a tomographic series with the corresponding ideally angulated radiographs of the condyle section depicted. A fair degree of fidelity of the radiographic image of the tomographic radiograph was observed. However, tomographic radiographs exhibit some magnification and are not as sharp and clear as conventional radiographs.

Complete denture secondary impression technique to minimize distortion of ridge and border tissues.

A technique has been described with which a physiologic and anatomic registration of the attached and unattached tissue of the denture-bearing areas can be attained. Clear acrylic resin trays aid in eliminating excessive displacement at the secondary impression phase. Inadequacies of the mucostatic concept include: Failure to register the tissues, which are important for retention and stability Certain metal bases that are part of this procedure can be implemented by only a small number of technicians Increased cost There are two shortcomings of the tissue-loading technique for complete denture impressions. Resulting retention and stability lasts only for a short period of time. Unwanted ridge resorption and tissue changes occur.

Uses and abuses of the tissue treatment materials

Abstract A clinical study was made to evaluate the ability of the tissue treatment materials to improve the health of oral tissues traumatized by ill-fitting dentures. The ability of the tissue treatment material to accomplish that goal was dependent upon the prior correction of the trauma-causing factor. Dentures constructed after the tissue conditioning materials were used for making the final impressions were not superior in retention and stability to dentures made from other types of impressions.

Stabilized record bases for complete dentures

A step-by-step technique has been described to construct stabilized record bases which allows the dentist to take advantage of undercuts through the use of a resilient denture liner material in the undercut regions. The resilient denture liner material protects the rugae and prevents damage to the casts in the undercut regions during repeated placing and removal from the cast. Shellac denture base material at the posterior limit of the record base permits an easy method of checking the posterior palatal seal. The incorporation of the posterior palatal seal in the record base allows for adequate retention during the recording of the maxillomandibular jaw relation records and try-in procedures. The record bases made by the sprinkle-on technique are preferred to those made using the dough method. The bases are rigid, stable, not easily broken or warped, and fit accurately.

Physiologic determinants of primary impressions for complete dentures

A technique has been described whereby a physiologic registration of the attached and unattached tissues of the denture-bearing areas can be attained. A low-fusing impression wax in conjunction with modeling compound is used for this purpose.

A comprehensive approach to tissue conditioning for complete dentures

I 11-fitting dentures are abusive to the underlying soft tissue and can induce deformation and inflammation. The need for conditioning oral tissues to a healthy state prior to making impressions for new dentures has been documented.‘-‘5 Untreated deformed tissues compromise the stability and retention of new dentures and may result in changes of occlusal relationships (Fig. 1). The purposes of this article are to (1) identify the key deficiencies of poorly constructed complete dentures, (2) present a technique to correct them, and (3) describe the application of tissue-conditioning materials in this more favorable environment. If the. material is used in existing dentures without prior correction of the deficiencies, therapy will not be successful and its potential will not be realized. The deficiencies most frequently encountered are inadequate border extension, incorrect vertical dimension of occlusion, and lack of a harmonious occlusion. Each of these features must be evaluated and corrected in an orderly fashion to obtain optimum results.

A loading impression technique for semiprecision and precision removable partial dentures

The rationale of designing a seimprecision or precision distal-extension removable partial denture and the justification of ridge loading in distal-extension ridge impression techniques have been presented. The effectiveness of existing impression techniques in securing firm seats for abutment castings, accurate border extension of the denture base, and loading of the ridge mucosa has been evaluated. A technique has been described that overcomes the limitations of existing impression techniques for semiprecision and precision distal-extension removable partial dentures.

The effect of thyrocalcitonin and growth hormones on bone metabolism

The use of the hormone, thyrocalcitonin, has been shown to change the bone metabolism so that resorption is decreased and calcium increased. The growth hormone seems to add to bone mass and indirectly prevents resorption. The combination of growth hormone and calcitonin seems to cause an unusual amount of resorption. This research has shown that metallic endosteal blade implants are not automatically successful even in short spans with additional support from two abutment teeth. It is true that the type of occlusion of the squirrel monkey is different from that of man, but the prosthetic devices that were placed in these animals can be validly compared to similar devices placed in man. While the hygiene cannot be practiced effectively by the animal, the psychogenic and emotional problems of man offset this disadvantage. Also, the diet of the monkey is not as traumatic to a prosthesis as is mans. Two of the most important criteria for implant success have not proved satisfactory: (1) no pocket depth beyond 3 mm. and (2) negative radiographic pathosis around the implant. While this study was not meant to be one of criticism or evaluation of metallic implants, it should be noted that thyrocalcitonin and the growth hormone, individually used, played an important part in retarding bone resorption around the blade. Autogenous bone grafts for residual alveolar ridge restoration often fail due to rapid osseous resorption and volume loss. The maintenance of osseous elements in the autogenous bone grafts when calcitonin had been administered was quite revealing. This might be the chemotherapeutic basis for the many conditions involving bone that dentists are called upon to treat.