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Biomedical subjects

R E Walton

Publications and source records attributed to R E Walton.

At least 91 records · Page 5Linked to original sources
PubMed1984

Fluoride levels in dentin after iontophoresis of 2% NaF.

The fluoride in successive layers of dentin (from 3-6 micron were removed per etch) has been measured following topical or iontophoretic application of 2% aqueous sodium fluoride to coronal exposed dentin of freshly extracted human third molar teeth. The fluoride contents of the topical and iontophoresed first etches were, respectively, 12 and 22-31 times greater than that of control (untreated) teeth. Similarly, the fourth etches were 12 and 50-70 times greater, and the seventh (last sampled) etches were 5 and 28-41 times greater. There was no apparent change in acid solubility of the dentin as its fluoride content varied under the conditions of this study. This is the first report studying the fluoride content of extremely thin layers of dentin successively removed by acid etch and relating topical to iontophoretic uptake.

Acid Etching, Dental↗
PubMed1984

Effect of occlusal relief on endodontic pain.

It has been suggested that removal of occlusion contacts will prevent or reduce postoperative endodontic pain during treatment. However, this theory has not been tested in clinical experiments. In this study, after endodontic instrumentation, the treated posterior tooth randomly received occlusal relief or mock-occlusal relief. Mean pain levels and the incidence of pain to occlusal pressure at various time intervals were recorded on questionnaire postcards by all patients, as was the duration of discomfort. Comparison of pain experienced by the occlusal treatment groups through statistical analysis gave the following conclusions: Spontaneous pain levels in the mock-occlusal relief and occlusal relief groups were not significantly different; Spontaneous pain levels in the mock-occlusal relief and occlusal relief groups did significantly relate to preoperative pain; Pain incidence from occlusal pressure in the mock-occlusal relief and occlusal relief groups did not significantly differ; Pain from occlusal pressure in both occlusal treatment groups did not significantly relate to preoperative pain; Duration of discomfort was not related to the occlusal treatment provided. The theory may be invalid that prophylactic removal of occlusal contacts is a pain preventive measure.

Dental Occlusion, Balanced↗
PubMed1984

Intracanal medicaments.

Intracanal medicaments in endodontics have been used for a number of reasons both in the past and currently. These include the elimination or reduction of microorganisms, rendering canal contents inert, prevention of post-treatment pain, and to enhance anesthesia. The chemical nature of medicaments employed are varied; they come from a number of different groups. Often, different chemicals or drugs are combined in a "cocktail" in an attempt to elicit a variety of effects with a single application. After reviewing in vivo and in vitro research, there is a decided lack of evidence of the clinical effectiveness of intracanal medicaments, with the exception of steroids for prevention of pain. What is clear from the research, is the toxicity and potential allergenicity of the commonly used intracanal medicaments, particularly those of the phenolic and aldehyde derivatives. Ready accessibility to periapical tissues and systemic circulation raises serious doubts as to whether their use is safe. It is also unlikely that most medicaments enhance clinical success. Considering the research, the findings of which are reinforced by clinical experience, intracanal medicaments are primarily useless. The one exception is intracanal or systemic steroids. They are effective in reducing the incidence of post-treatment pain.

Anesthesia, Dental↗
PubMed1983

Periodontal ligament injection: distribution of injected solutions.

In a simulation of the clinical technique, a radiopaque solution and a colloidal carbon suspension were injected into the periodontal ligament in dogs by means of a standard syringe. The colloidal carbon method was superior and demonstrated that the injected material was found in soft tissue and adjacent hard structures and in the vessels of the pulps of the immediate and adjacent teeth. The distribution of the dye did not relate to the injection volume and needle location but was consistently more widespread when injections were given under moderate to strong pressure. The technique appears to be a form of intraosseous injection.

Anesthesia, Dental↗
PubMed1983

Clinical evaluation of periodontal ligament anesthesia using a pressure syringe.

Conventional local anesthesia techniques are frequently unsuccessful, particularly for endodontic procedures. Supplementary injections are often necessary; the periodontal ligament injection is useful for this purpose. This study examined the effectiveness of injecting into the periodontal ligament with a pistol-type pressure syringe as a supplemental technique in patients who did not have adequate anesthesia for endodontic therapy. Sixty patients received the supplemental injections and 20 patients were reinjected when the first PDL injection failed. Data were obtained by questionnaire. Percentages were computed and comparisons made by X2 analysis. The conclusions about attaining anesthesia included: --Needle size was not important; overall, 25- and 30-gauge needles were equivalent. --Injecting under strong back-pressure was important; the greatest frequency of success was attained when injecting under pressure. Lack of back-pressure on both mesial and distal surfaces resulted in a significantly lower incidence of anesthesia. Proper positioning of the needle and maintaining this position, to force the anesthetic deep into the periodontium, is apparently an effective way to generate the needed back-pressure. --Strong back-pressure could usually be attained on either or both surfaces. --Reinjection was frequently successful if the first periodontal ligament injection failed. --Overall frequency of success in attaining anesthesia with the pistol-type pressure syringe was 83%. This was determined by including the instances in which reinjection was necessary. --Comparing the results of this study with a previous similar study, the pressure syringe were equally effective for supplementary anesthesia.

Anesthesia, Dental↗
PubMed1982

Characterization of the periapical surgical specimen. A morphologic and histochemical study of the inflammatory patterns.

Biopsies of human periapical lesions obtained during endodontic surgery were studied morphologically and histochemically to determine the nature of the inflammatory reaction. Evaluation was based on cell types, morphologic patterns, degree of cellular infiltration, extracellular components, and their interrelationships. Almost all periapical lesions showed the characteristic features of granulomatous inflammation; chronic (nongranulomatous) inflammation was a lesser component of the reaction. Acute inflammation was seen either as focal concentrations or as scattering of polymorphonuclear neutrophilic leukocytes in variable numbers throughout the chronic and granulomatous inflammatory tissue. Epithelium was noted in one third of the specimens. Granulation tissue was not seen. Thus, granulomatous inflammation appears to be a consistent inflammatory reaction pattern in periapical lesions.

Collagen↗
PubMed1981

Periodontal ligament injection: a clinical evaluation.

Attaining profound local anesthesia is frequently difficult. Standard block or infiltration injections often are not sufficient; a supplementary injection is often necessary. The purpose of this study was to examine the effectiveness of the periodontal ligament injection in patients who did not have adequate pulpal anesthesia. Information was obtained by questionnaire after 120 periodontal ligament injections. The frequency and rapidity of onset of anesthesia was determined as well as the factors that might affect the technique. The following conclusions were obtained from this study. -Mandibular molars required supplementary anesthesia more frequently than other types of teeth. -Injecting under strong backpressure was important; the greatest frequency of success was attained when injecting under pressure. Injecting without strong pressure on both mesial and distal surfaces resulted in the lowest frequency of anesthesia. -Onset of anesthesia was generally very rapid, usually immediate. -The length and gauge of needle were unimportant in attaining anesthesia. -Rejection was frequently successful if the first periodontal ligament injection failed. -The overall frequency of success in attaining anesthesia with this injection was 92%. This rate included situations in which the injection was administered more than once. -The most critical factor was to inject under strong resistance. This necessitates wedging the finger supported needle into the interproximal space between root surface and bone and applying maximum pressure to the syringe handle.

Anesthesia, Dental↗
PubMed1979

Effects on pulp and dentin of iontophoresis of sodium fluoride on exposed roots in dogs.

Experiments were performed on young permanent teeth in which there was demonstrable active dentin formation. Following surgical exposure of roots and removal of cementum with scalers, 1 percent sodium fluoride in aqueous solution was applied either topically or with direct-current iontophoresis. Two levels of current, therapeutic or five times therapeutic, were used. Observation periods were 7 and 80 days. There were no demonstrable histologic or ultrastructural alterations of the underlying pulp; nor was there a resultant change in the rate of dentin formation. While exposure of root surface dentin alone (negative control) produced no alterations, grinding the surface (positive control) caused noticeable changes in dentin, odontoblasts, and pulp.

Animals↗
PubMed1978

Dentin permeability: determinants of hydraulic conductance.

A technique is described which permits measurements of the ease with which fluid permeates dentin. This value, the hydraulic conductance of dentin, increased as surface area increases and/or as dentin thickness decreases. It increased 32-fold when dentin was acid etched due to removal of surface debris occluding the tubules.

Acid Etching, Dental↗