The decade of overdentures: 1970-1980.

Jaw bones resorb when teeth are lost. People cannot function as well with complete dentures compared with their natural teeth. As more people are living longer and these cumulative effects become increasingly documented, dentists in the 1970s attached more importance to keeping teeth. The concept of overdentures developed as a simple and economic alternative to prolong the retention and function of the last few teeth in a compromised dentition. The previous option was extensive fixed prosthodontics. An overdenture is a complete or removable partial denture that has one or more tooth roots to provide support. Rather than extracting all compromised teeth, the crowns, and pulpal tissue of selected teeth (usually two anterior teeth) are removed. The remaining root projecting through the mucosa is restored and/or contoured. With the crown removed, there is space to cover the area with a denture. The root has less mobility, and its retention retards bone resorption. Overdentures with roots are more stable, and patients can chew better than with dentures supported on residual alveolar bone and mucosal tissue alone. Keeping even a few teeth has a strong psychological value for some patients. Patients who have lost teeth, adjacent tissue, and bone need replacement of more oral structures than tooth crowns alone can provide. A complete denture with flange contours can restore tissue and appearance. The conventional tooth-supported overdenture concept continues to be an accepted treatment modality and has now been adapted to implants.

Retention of metal ceramic crowns cemented with resin cements: effects of preparation taper and height.

This study investigated the effect of varying crown preparation taper and height on the retention of metal ceramic crowns cemented with resin cements. In part 1, 32 extracted molars were divided into four groups. All groups received complete-veneer crown preparations, two with a 12-degree wall angle and two with a 35-degree wall angle. Crowns were cemented with zinc phosphate and dentin-bonded resin cements. After 24 hour water storage at 37 degrees C, the crowns were separated in tension. Crowns cemented with zinc phosphate were cleaned and recemented with another dentin-bonded resin cement and after similar storage, the crowns were separated. Mean separation forces of resin-cemented crowns were higher than those of crowns cemented with zinc phosphate cement. Mean separation force of 35-degree crowns cemented with one dentin-bonded resin cement was found to be significantly higher than for the 12-degree crowns cemented with zinc phosphate cement. In part II, 32 extracted molars were divided into two groups of complete-veneer crown preparations (group I preparations were 3 mm high and group II were 5 mm high). Crowns for all teeth were cast and cemented with zinc phosphate. After 48 hours' water storage at 37 degrees C, the crowns were separated in tension. Crowns and teeth were then cleaned and each group was subdivided into 2 equal subgroups. In one subgroup of teeth with 3 mm and in one with 5 mm high preparations, the crowns were recemented with one of the two resin cement systems and the other two subgroups were recemented with the other resin cement. After 48-hour water storage, the crowns were separated. Mean separation forces of the resin-cemented crowns were greater than those of crowns cemented with zinc phosphate. Also, mean separation force of 3 mm crowns cemented with one resin cement was significantly greater than the 5 mm crowns cemented with zinc phosphate. Cohesive dentin fracture on separation was observed with some resin-cemented crowns but never with crowns cemented with zinc phosphate.

Removable partial prostheses for the elderly.

Elderly partially edentulous patients can have teeth replaced with removable or fixed prostheses supported by mucosa, teeth, or implants. Age per se does not influence which option is best. Instead, the relative health of the patient, dental tissues, and the patient's finances determine treatment. A three-level index of these factors, the PTF index, is proposed to assist in the decision-making for treatment. Removable partial prostheses (RPPs) can be indicated for all patients because RPPs offer esthetic, versatile, noninvasive, and reversible features. They are particularly indicated when remaining teeth are questionable. If teeth are lost, they can be more easily added to existing RPPs compared with fixed prostheses. Six changes to ideal designs are illustrated in this article for prostheses with a compromised dentition, to make continued prosthetic service simpler.

Modern concepts in nonsurgical management of traumatic biliary fistulas.

The management of traumatic biliary fistulas is controversial. New ideas in nonsurgical treatment have recently evolved, in part because of the rapid advancement of laporoscopic surgery. Three major concepts are important in managing biliary fistulas: diagnosis, drainage, and decompression. These concepts were applied to a trauma patient, then reviewed in detail.

Research status of prosthodontic procedures.

In the last decade, the success of osseointegration has encouraged dentists internationally to use titanium implants to assist in the replacement of tissue, ranging from a single tooth to facial prostheses. Investigations have focused on more sophisticated treatment planning, improved clinical procedures, selection of better materials, development of superior components, and reduced treatment time. The introduction of procedures from other industries has brought a new level of standardization and quality control to the fabrication of prostheses.

Prevention of stress gastritis with tissue preservation solution.

Stress gastritis frequently occurs in association with shock or sepsis. Gastric mucosal ischemia appears to be a key feature in these critically ill patients. The University of Wisconsin cold preservation solution (UWS) is an isoosmolar, nonglucose-based perfusate that minimizes hypothermia-induced cell swelling and prevents intracellular acidosis and oxygen-free radical injury, while providing high energy substrates for donor organs. In a prospective, single-blind study, 18 similar Sprague-Dawley rats were randomly divided to receive only 5 per cent dextrose and water (D5W) (Group 1) or a 50 per cent solution of D5W+UWS (Group 2) for 72 hours. At the end of 72 hours the animals were stressed by the cold-restraint model. The mean number of ulcers for Group 2 was nearly half that of Group 1. Also, Group 2 had a significantly lower mean total ulcer length (P less than 0.005) and ulcer index (P less than 0.05). Most of Group 2 had mild gastritis changes (grade 0 to 1), while more than half of Group 1 had severe gastritis (grade 3). Gastric mucosal pH was similar for both groups. Topically applied UWS appears to reduce the severity and incidence of stress gastritis in this experimental model. Because mucosal pH values were similar, it is thought that UWS may alter the effects of gastric mucosal ischemia at a cellular level.

The utility of intraoperative cholangiography with acute cholecystitis.

An increasingly important subset of patients with biliary tract disease are those with acute cholecystitis. The indications for both routine or selective intraoperative cholangiography (IOC) during elective cholecystectomy may not be appropriate for this group. The utility of IOC in the presence of acute cholecystitis was examined. The medical records of 223 patients with histologically confirmed acute cholecystitis were reviewed. Clinical and laboratory criteria included age, sex, white blood cell count (WBC), serum bilirubin and alkaline phosphatase levels. In 52 (23%) patients, IOC was not attempted and was technically unsuccessful in 15 (7%) patients. IOC was successful in 156 (70%) patients and, of these, six (4%) had a false-positive examination. The remainder are divided into two groups. Group 1 (131 patients) had true-negative IOC, whereas Group 2 (19 patients) had true-positive IOC as evidenced by stone recovery upon surgical exploration. When comparing Group 2 with Group 1, the mean preoperative laboratory values are higher; these differences do not reach statistical significance. Further, within Group 2, five (26%) patients did not demonstrate any clinical or laboratory elevations suggestive of common duct pathology. Thus, in acute cholecystitis, laboratory criteria do not appear to discriminate between the presence or absence of choledocholithiasis. IOC is advocated as an integral component of the operative procedure.

Changing concepts of deep venous thrombosis of the upper extremity--report of a series and review of the literature.

Deep venous thrombosis (DVT) of the upper extremity has recently been recognized as being more common than previously reported (probably because of the increasingly frequent use of subclavian venous access). A retrospective review of patients in whom subclavian or axillary DVT had developed in the past 6 years (1980 to 1986) was conducted at the Akron General Medical Center. The major cause identified was related to subclavian venous catheterization, which accounted for 39% of all instances of subclavian and axillary DVT. Our results are correlated with a review of the literature. In our review of studies in which subclavian venous catheterizations were prospectively examined with use of objective means of diagnosis, we found that 28% of all subclavian catheterizations had venous thrombosis develop, often subclinically. This is not an innocuous disease, as suggested in the past; in our series 12% of upper-extremity DVT had pulmonary embolization (PE). In reviewing the recent literature, we found an average 12.4% incidence of PE, which often occurs during anticoagulation treatment. Diagnostic modalities are discussed and treatment regimens are reviewed along with an extensive literature review.

Overdenture oversights.

Overdenture oversights can occur in the following areas: patient selection, hard and soft tissue preparation, laboratory procedures, or post-placement maintenance. If the dentist takes steps to control these factors, overdenture therapy can be an enjoyable and satisfying part of his service to his patients. Certainly the measures outlined in this article require minimal effort, and should be included routinely in treatment.

Tissue response to overdenture therapy.

Patients who had received overdenture treatment provided with uniform standards were recalled and studied. Two examiners simultaneously and independently evaluated the tissue response using a variety of indices. Data comparisons were made between overlaid teeth and control teeth and between overlaid teeth as a function of time to assess any effects of the treatment. Patients who did not apply fluoride to retained tooth roots had a high incidence of caries. No other significant differences were noted between the health of overlaid teeth compared to control teeth. Patients demonstrated large variations in their ability to maintain low plaque levels and healthy tissues. Despite this, on a longitudinal basis over 2 years, patients were able to maintain plaque levels and gingival response at clinically acceptable standards.

Interim overdentures.

The construction of an interim overdenture using existing removable partial dentures with natural tooth crowns and artificial teeth can be a simple and economical method of providing patients with dentures while tissues heal and teeth are prepared and restored. A more definite prognosis for both the patient and his remaining dentition can be established before the final overdenture is completed. The procedures necessary to provide three types of interim overdentures have been outlined. Patients tolerate this method of changing their dentitions extremely well.