Perioperative hemodynamic changes in ischemic heart disease patients undergoing dental treatment.

Twenty patients with stable ischemic heart disease in functional capacity Class II-IV underwent dental treatment. Scaling was performed in seven patients without local anesthesia. In the remaining 13 patients, pain control for restoration placement was obtained by local anesthesia: in seven patients, the anesthetics contained epinephrine, while in six this drug was omitted. Heart rate, blood pressure, and electrocardiograph were continuously monitored during the dental session. All patients had elevated systolic blood pressure and rate pressure product during treatment. In the patients who received plain local anesthetics only, the elevation in systolic blood and rate pressures was, however, significantly lower than the ischemic threshold. Arrhythmia or ST segment depression of > or = 1 millimeter were not recorded in any of the subjects. In severely compromised ischemic heart disease patients undergoing routine dental procedures of limited chair time, plain local anesthesia seems to be the preferred analgesic modality.

The effects of beam hardening on digital subtraction radiography.

Quantitative assessment of osseous changes attributable to periodontal disease is made possible by digital subtraction radiography. Tissues through which x rays travel to produce dental radiographs essential to this process alter the energy spectrum of the beam such that calibration errors result when densitometry is attempted using a homogeneous calibration standard such as a step wedge. The following controlled in vitro investigation evaluates the extent of such errors caused by these spectral differences, called beam hardening. Simulated osseous lesions of known size were computed densitometrically using selectively filtered radiation to produce the x-ray images. The resulting data confirm the theory and demonstrate with statistically meaningful accuracy that beam hardening can contribute a significant component of variance to absolute estimates of lesion size. They also suggest that other errors (probably attributable to low contrast) may be even more important at high peak kilovoltages.

Development of resistant oral viridans streptococci after administration of prophylactic antibiotics: time management in the dental treatment of patients susceptible to infective endocarditis.

The American Heart Association recommends prophylactic administration of penicillin before each dental session to patients susceptible to infective endocarditis. Such preventive treatment, however, may trigger the transient appearance of penicillin-resistant bacterial strains. In order to investigate the behavior of oral streptococci, 29 healthy volunteers who did not harbor penicillin-resistant viridans streptococci received 4 gm of phenoxymethyl penicillin orally over a period of 10 hours. This amount constituted the sole dose of antibiotics administered in the entire experiment. Daily specimens of oral flora were obtained for 14 successive days from each participant and incubated aerobically with a penicillin-saturated disk for 24 hours. Viridans streptococci were considered resistant when bacterial colonies grew adjacent to the disk for 1 day or more. The study population was divided into high- and low-resistance groups, according to the individual antibiograms. Resistant viridans streptococci were already detected at 6 hours after penicillin ingestion in nine (31%) of the subjects. Six months later, oral specimens were taken from ten randomly selected participants; these specimens served as a control. The difference in bacterial resistance between the high- and low-resistance groups was significant for the duration of 9 days, as was that between the high-resistance and control groups (p less than 0.05 in both cases). In order to minimize the odds that penicillin-resistant bacterial strains will develop in patients susceptible to infective endocarditis, elective dental treatments in these persons should be scheduled in intervals of not less than 10 days.

Prevention of infective endocarditis: not by antibiotics alone. A 7-year follow-up of 90 dental patients.

Ninety patients (thirty-nine men, fifty-one women with a mean age of 45.4 years with rheumatic heart disease or prosthetic heart valves, were subjected to a total of 1617 dental procedures, which required about 3400 patient/dentist encounters. All treatments were performed according to the protocol described in the present article. Although theory expects three to six cases of infective endocarditis cases in the described population, none of the patients have encountered the disease (p = 0.0013). A conceptual approach, as well as the protocol, is presented. Properly applied, the protocol will reduce the probability of iatrogenic and self-inflicted bacteremia, thus elevating the efficacy of the preventive process.

Analysis of the American Heart Association's recommendations for the prevention of infective endocarditis.

A probabilistic model analyzes the American Heart Association's (AHA) recommendations for the prevention of infective endocarditis (IE) of dental origin. The model, presented in the form of a flow chart, combines available data elements with the AHA recommendations; mortality serves as the sole valued outcome and payoff measure. The analysis shows that an annual death rate of 1.36 per million population is attributable to the antibiotics administered in an attempt to prevent IE, whereas not more than 0.26 annual deaths per million are traceable to IE of dental origin. Sensitivity and threshold analyses were conducted to determine the conditions under which the recommended prophylactic policy will prove beneficial. The model suggests that the standard AHA antibiotic regimen should be exploited only in IE susceptible patients belonging to the high risk categories and that its value in moderate, low, and negligible risk patients is doubtful. When the use of antibiotics is unavoidable, oral administration is the preferable route.

Dental treatment for the patient on anticoagulant therapy: prothrombin time value--what difference does it make?

Thirty patients taking anticoagulants received routine dental treatment without altering their prothrombin time values. In a follow-up of 5 years, no serious complications were seen in patients with a prothrombin time value of up to 2.5. A protocol is suggested for dental treatment in these patients.

How often should a preventive procedure be repeated? An economic analytic model applied to dentistry.

Operation research techniques have successfully been applied to economical order situations. An Economical Recall System (ERS) model, based on this theory, is proposed for curative and preventive dental care. The ERS model assumes a preventive procedure with no lead time between application and initiation of effect, an immediate decline in morbidity level once the effect is initiated, and linear increasing rate of morbidity. The model also assumes a positive net present value of the prevention program and therefore the question approached is the optimal time sequence at minimal cost. The model supplies a valuable tool for analyzing the effect of the curative, preventive and administrative components of a program and how changes in each, or any combination, of these variables will affect the end results.

Alveolar bone repair following extraction of impacted mandibular third molars.

Bone regeneration following extraction of impacted mandibular third molars was measured on 83 preoperative and postoperative radiographs. The patient sample was divided into two age groups, 20 to 29 years and 30 to 50 years. Postoperatively, there was an average net gain of 2.15 mm in bone level. The degree of bone healing is affected primarily by age and, to a lesser extent, by the presence of generalized inflammation (periodontitis).

Pulpitis and root canal therapy: is a diagnostic radiograph of value?

Historical data and a decision-flow diagram were used to analyze the informational value to be obtained from diagnostic radiographs in cases of pulpitis. It is recommended that preoperative radiographs be relegated to the category of nonroutine procedures and that the eccentric length-measurement radiograph be used as point of reference.

Optimal student-patient assignment in dental education.

This paper presents a constrained optimization model for the assignment of patients to dental students in a dental school clinic. Issues of efficiency, educational requirements, facility constraints, faculty constraints, and continuity of care are addressed in the model. A test problem and solution are used to illustrate the managerial impact of the model.

The spatial distribution, intensity and unpleasantness of acute dental pain.

The distribution, intensity and unpleasantness of acute dental pain were studied in 196 patients. Dental pain was classified by source according to 7 anatomical sites: dentinal, pulpal, pulpal and periapical, periapical, pericoronal, papillar, and periodontal. The distribution of dental pain was classified by the frequency of pain spread throughout the sample, by the extent of pain spread for a particular pain source, that is, the number of vectors of spread, and by the pain reference locations in the face and head. Pain-intensity and pain-unpleasantness were assessed on Visual Analogue Scales. The frequency and extent of pain spread varied as a function of source. However, specific patterns of pain spread were not associated with particular pain sources. There was considerable overlap in patterns of spread between maxillary and mandibular pain sources. The frequency and extent of pain spread was correlated positively with both pain intensity and pain unpleasantness. The correlation between pain ratings and pain spread may be attributed to central mechanisms and interactions between trigeminothalamic neurons. Spatial overlap of pain from maxillary and mandibular pain sources may be due to the large receptive fields of wide dynamic range neurons, that can extend beyond one trigeminal division. These observations indicate that the spatial distribution of acute dental pain is not sufficient as a diagnostic tool for indentifying pain source.

Hospital personnel with penicillin-resistant Streptococcus viridans. A case for special consideration in the prevention of bacterial endocarditis.

Penicillin is the drug of choice for the prevention of bacterial endocarditis (BE) resulting from dental treatment. The susceptibility of Streptococcus viridans to this antimicrobial agent was studied. A representative sample of hospital personnel (N = 76) was compared to a control group of seventy-six subjects who were not associated with the hospital. Twenty-four of the hospital personnel worked in wards that consume 0.13 to 1.64 (mean +/- SD = 0.88 +/- 0.64) gm penicillin per day per position (low consumption group = LCG) and fifty-two worked in wards that consume 2.27 to 3.67 (mean +/- SD = 3.04 +/- 0.55) gm penicillin per day per position (high consumption group = HCG). Antibiograms of oral isolates showed that, while 48.08% of the subjects from the HCG revealed penicillin-resistant S. viridans only 8.33% of the subjects from the LCG and 7.89% of the control group presented such results. The data presented suggest that there are subjects who may unknowingly carry penicillin-resistant S. viridans as part of their oral flora. It is therefore recommended that the preferable antibiotic used for the prevention of BE should be determined by an antibiogram.

A computerized decision support system for patient selection in dental education.

A computerized decision support system is presented. The system is used to aid in the situation of patient selection for the purpose of dental education and utilizes the PERT/CPM methodology and decision tables. It runs on a microcomputer and written in Basic. The input is a list of patient's needs, and the output is a tentative treatment plan, the chair time needed to complete the treatment, its cost, and the probability that the student will finish it on time.

Electroconductivity of bone in vitro and in vivo.

In view of conflicting data in the literature regarding the electroconductivity of bone, measurements were performed both in vivo and in vitro by using alternating current of 100.0 mA and 1.0 mA at a frequency of 1000 cycles/second and the four-electrode method. Electrodes were inserted through all of the bone layers into the bone marrow space of the femora of seven rabbits. Bone electric resistance was measured also in situ 30 minutes after the death of the animals. A threefold increase in resistance of bone, from about 600 to about 1700 ohm, occurred in situ 30 minutes after the death of the animals, and an enormous resistance, about 10(10) ohm, was measured in vitro. It was also apparent that femora from the different rabbits had different values of electric resistance both in vivo and in vitro. If electroconductivity of bone is determined by body fluids rather than by the bone tissue per se, measuring the "specific resistance" of bone in vivo is meaningless.

Electroconductivity of collagen in vitro and in vivo.

Electrical conductivity was measured on thermally reconstituted collagen fibers in vitro and on isolated rat tail tendon collagen fiber bundles in vivo. The results obtained indicated that collagen per se is not an electroconductor under physiological conditions, but rather a biological insulator.