Samuel S Patterson's research while affiliated with University of Minnesota Twin Cities and other places

The frequency of the creation of apical dentin plugs in unifected monkey teeth with vital pulps and their effect on healing of filled and unfilled canals were investigated. Two male monkeys, one Macaca mulattaand one Macaca speciosa, were used for a 9-and 12-month study. Forty-three root canals in 33 teeth prepared 0.5 to1 mm from the radiographic apex were studied histologically. Thirty-one experimental canals were not filled after instrumentation and 12 control canals were filled by lateral condensation of gutta-percha and sealer after instrumentation. After both 9 and 12 months, there was a less than23% incidence of inflammation associated with the periapices of the experimental group that had his-tologically apparent apical dentin plugs. Similarly, there was a less than 18% incidence of inflammation associated with the periapices of the control canals that had plugs. Inflammation was much more common (90%) in both the experimental and control canals without plugs. Statistical analysis showed that canals with plugs (experimental and control) had less inflammation than canals without plugs.

We examined 30 male chronic hemodialysis patients and 18 male controls without known bone or renal disease to determine the utility of maxillomandibular, non-dominant hand, shoulder and pelvis films in the evaluation of renal osteodystrophy. We used panoramic periapical radiographs to examine the maxilla and mandible and sensitive rapid processing films for the hand, shoulder and pelvis. Films were evaluated by experienced personnel without knowledge of the patients. There were significant differences between patients and controls in creatinine, urea nitrogen, total protein, albumin, alkaline phosphatase and phosphorus. Twenty-three patients had abnormal hand radiographs and 22 patients had abnormal jaw radiographs (p less than 0.05 vs. controls). Four patients had changes in the hands, but not in the jaw; 4 had opposite findings. Changes in the jaw tended to be more severe than in the hands in those with involvement of both. We concluded that dental and hand radiography are good screening techniques for evaluating bone disease. They may be useful in evaluating treatment for renal osteodystrophy.

Fue investigado el efecto de la preparación del conducto en la formación y filtración característicos del tapón apical dentinario. Fueron instrumentados con limas del no 1 al 5 consecutivamente 70 conductos radiculares de dientes humanos extraidos. Los dientes fueron sumergidos en Ca45, seccionados y autoradiografiados para determinar la filtración apical. Fueron examinadas varias muestras al microscopio de barrido electrónico para determinar la naturaleza del tapon apical. Habría una tendencia general segun la cual con un mayor grado de preparación del conducto disminuiría la filtración. El estudio a traves del microscopio de barrido electrónico mostró que el proceso de la formación del tapón de dentina, es un empaquetamiento gradual de partículas de dentina dentro de la región apical del conducto, usualmente sobre tejido pulpar residual. A medida que la preparación continua se genera mayor proporción de partículas de tejido duro en proporción al tejido blando. En el período inicial de la instrumentación el tapón resultaría fibroso lo cual no detiene la filtración.

This clinical study was undertaken to determine whether endodontic therapy affected the cardiovascular physiology of 30 patients with pulpal pathosis, as evidenced by changes in blood pressure or heart rate, or by arrhythmia. Regardless of the type of pathosis, mean systolic and diastolic blood pressures and mean heart rates were similar during the various procedures at each appointment or at successive appointments. However, these parameters were significantly higher in patients treated for pulpitis or symptomatic necrosis than in patients treated for asymptomatic necrosis. This was attributed to the presence and severity of pain. Seven of the 30 patients had episodes of arrhythmia that could not be related to a specific procedure, appointment, or type of pulpal pathosis. On the basis of these findings, it appears that nonsurgical endodontic therapy has no effect on the cardiovascular system of patients with no known history of cardiovascular disease. However, the type of pulpal pathosis may produce statistically significant cardiovascular changes.

Sixty single-rooted teeth were endodontically treated by two postgraduate students for asymptomatic pulpal necrosis. Thirty were treated in a single visit each, and a control group of 30 were treated in three visits each. Clinical and radiographic evaluations were made. A subjective questionnaire was used to record pain experience. No significant difference in the incidence of pain existed between the single- and multi-visit groups.

A comparison was made of the effectiveness of irrigation with 0.2% chlorhexidine gluconate solution and 2.5% sodium hypochlorite solution during the endodontic treatment of 60 asymptomatic, uniradicular teeth with necrotic pulps. The effects of the two irrigants were monitored through aerobic and anaerobic bacteriologic cultures, which were obtained at the beginning and end of each appointment. As an endodontic irrigant, sodium hypochlorite solution (2.5%) was significantly more effective as an antimicrobial agent than chlorhexidine gluconate solution (0.2%).

Forty freshly extracted teeth with necrotic pulps were endodontically treated under simulated clinical conditions. Bacteriologic samples were obtained before during, immediately after, and 24 hours after instrumentation, irrigation, and medication either with 0.2 percent chlorhexidine gluconate or with sterile saline. There was a highly significant (p less than 0.0049) reduction in microorganisms in the chlorhexidine-treated specimens after the instrumentation and irrigation procedures. Further significant reductions were noted after intracanal dressing of the teeth for 24 hours with the chlorhexidine gluconate solution. The teeth treated with saline also demonstrated a generalized decrease in flora after the biomechanical procedures. However, there was an absolute increase in numbers of microorganisms for 80 percent of the uniradicular and 50 percent of the multiradicular specimens when no intracanal, antimicrobial dressing was applied. It was concluded that chlorhexidine gluconate in a 0.2 percent solution can be an effective antimicrobial agent when used as an endodontic irrigating solution and that as an intracanal, interappointment dressing, chlorhexidine helps to further reduce bacteria remaining within the root canal system.

With the use of a relatively simple anaerobic sampling technique, the contents of seventeen necrotic pulp canals were placed in two tubes containing endodontic culturing media. Growth in reduced thioglycolate was significantly greater than growth in unreduced trypticase-soy broth by a ratio of over 2:1.