James B. Lepley

Prefabricated dowels: A literature review

Abstract The various subtopics of post and core research were identified and reviewed. The literature in each subtopic was evaluated and conclusions were based on those evaluations.

Root fracture during insertion of prefabricated posts related to root size

T he consequence of inappropriate post selection and/ or hasty insertion can result in tooth fracture and/or loss.’ It has been demonstrated that conical or parallelsided post design has a direct effect on root fracture during post insertion. * However, during experimentation it became apparent that root size and its relationship to post size had a direct effect on root fracture. This article correlates root size, post size, and fracture rate during insertion of prefabricated posts. portion of each tooth was removed with a high-speed fissure bur at the level of the cementoenamel junction. The teeth were reamed with a No. 50 reamer to the apex, coated with a thin Silastic (Dow-Corning, Midland, Mich.) membrane to simulate the periodontal ligament, and embedded in a resin block that fit the testing apparatus (Fig. 2). Each root was measured five times before it was embedded. The resin, Silastic, and root test specimen were stored in water until tested.

Root fracture and the design of prefabricated posts

The derived signal is then converted to an analog signal for x-y recording and a digital signal for readout. A chart recorder takes the analog signal and displays it in an x-y format where the ordinate is torque (calibrated in inch-ounces) and the abscissa is angular rotation. The angular signal is developed from a five-turn precision potentiometer geared to the output rotor of the transducer (Fig. 1). Calibration of the system was accomplished according to the manufacturer’s procedure followed by application of a known fixed torque to a calibrated weight and beam. A correction of +3 inch-ounces was added to the measured readings as a calibration factor. The system was designed to generate a maximum torque of 200 inch-ounces; that magnitude was not exceeded during the experiment. Fig. 2. Resin, Silastic membrane, and tooth block in place in the XYZ movable fixture.

Mucormycosis in leukemia

Rhinocerebral mucormycosis is a virulent, rapidly progressive, potentially fatal illness which demands early diagnosis and aggressive medical and possible surgical therapy. Although most commonly reported in persons with poorly controlled diabetes, it may occur in other immunosuppressed hosts. In persons with leukemia the disease has been uniformly fatal. A well-documented case of fatal rhinocerebral mucormycosis in a leukemic patient is presented to illustrate the diagnostic and therapeutic dilemmas often faced. A review of the 233 cases thus far reported in the literature is used as a spring-board for a discussion of the pathogenesis, diagnosis, and management of this disease.

A technique for fabrication of polydimethylsiloxane-acrylic resin obturators

A flexible silicone obturator is an alternative to the acrylic resin obturator. It can be useful for patients with severe trismus who cannot insert a large prosthesis, as the flexibility of the hollow silicone section allows easy placement and removal (Fig. 9). Other patients cannot tolerate an unyielding substance against sensitive nasal tissues. Silicone can provide the necessary comfort without compromising retention. Silicone obturator sections can often be modified when further surgery is needed and result in a savings of time and expense (Fig. 10). For patients who can be reevaluated only twice a year, several silicone obturator sections can be made initially. One can be used while another is being cleaned or duplicated.

Torque placed by dentists on prefabricated threaded posts

Thirty-one dentists were tested relative to the optimal and maximum amount of torque they could deliver to posts in teeth. The mean for the optimal amount of torque was 15.55 ounce-inches, and the mean for the maximum amount of torque was 35.29 ounce-inches. Female dentists showed a statistically significantly lower mean difference of 24.5 ounce-inches on the maximum torque test.

The free-way space and its relation to the temporomandibular articulation

Vertical dimension is a nebulous position which is often left to the good judgment of the operator. Correct vertical dimension plays an important part, not only in the improved appearance of the patient, and in the comfort derived from dentures in function, but in the developing of the correct centric occlusion. The term “vertical dimension” is too often loosely construed to mean any distance between the upper and lbwer jaws. It is possible for the lower jaw to open and close over a great range. The range is limited in the opening position only by the ability of the closing muscles of the jaw to stretch to their limit, and by the ability of the depressors to contract. It is limited in the closing position by a tooth or ridge contact. Vertical dimension, as thus defined, becomes any jaw relationship between these extremes. The selection of the correct occlusal vertical dimension in denture construction has not been sufficiently stressed. A wide range of selection is left to the judgment of the operator, with a thought that too great a vertical dimension will create sequelae leading to discomfort and ridge destruction, but with little mention of the results of too short a vertical dimension. It

A flexible moulage for the fabrication of an orbital prosthesis

A technique is disucssed by which a flexible three-piece moulage may be fabricated. This procedure is a useful aid in the modeling of an orbital prosthesis. It permits the continued transfer of a wax pattern from the moulage to the patient utilizing the tissue undercuts for the retention and stabilization of the pattern. The critical task of properly positioning the ocular prosthesis is simplified by the increased stability of the entire pattern. This is of the utmost importance since even a slight error in the alignment of the eye can entirely negate the effect of an otherwise accurate prosthesis. In addition, the retention of the wax pattern simplifies the carving procedure, and accurate detail is easily secured. The acrylic resin surface on which the final silicone prosthesis is cured has proven to be accurate. Well-adapted, thin margins of the facial prosthesis have been consistently obtained.

The prong denture: A combined surgical-prosthetic approach to enhance denture retention

Abstract A technique is described where prong extensions were placed on a complete maxillary denture to fit into surgically created skin grafted pockets. Careful selection of patients who will follow oral hygiene instructions meticulously make the prong denture a viable alternative to complete denture construction for the severely resorbed residual alveolar ridge.

Fabricating a shoulder somatoprosthesis

A technique for the fabrication of a shoulder prosthesis has been described. The prosthesis has proven to be an effective means of rehabilitating a patient following an intrascapulothoracic amputation. The patient may once again wear clothing without having it adjusted to conform to the defect. Such rehabilitation has been of great psychologic value for patients and their families as well. The impression and processing procedures are effective for the fabrication of a shoulder prosthesis. The principles of this technique may be applied to the fabrication of other large somatoprostheses.