Endodontics and Endodontology Commons^™

Identification Of Risk Factors Associated With Pulpal Disease, Shelley R. Aronson

Loma Linda University Electronic Theses, Dissertations & Projects

A few studies have identified etiologic factors in pulpal disease, but little is known about the odds ratios of factors associated with pulpal disease. Odds ratios are well established measures of the effects of exposure to a particular outcome, and are comparisons of exposure to non-exposure in cases versus controls. The purpose of this study was to compare exposure of individual teeth to hypothesized risk factors in endodontic cases and in controls. This case-control study consisted of a chart review of 301 endodontic cases and 301 controls. Caries, types of restorations, and periodontal disease were the most significant factors. With …

Interleukin 1-Beta In Symptomatic And Asymptomatic Human Periradicular Lesions, Gerald C. Lim

Loma Linda University Electronic Theses, Dissertations & Projects

Interleukin 1-Beta has been shown to be a potent mediator of bone resorption and has been implicated in resorption in periradicular lesions. In this study we compared the local concentrations of IL-1β in symptomatic and asymptomatic human periradicular lesions. Periradicular tissues from patients with symptomatic and asymptomatic lesions were obtained and stored at -70°C. Pulpal tissues from unerupted third molars and chronically inflamed gingival tissues were also obtained and used as negative and positive controls, respectively. Tissue samples were homogenized, and supernatants were assayed for IL-1β by ELISA. Significantly higher levels of IL-1β were found in symptomatic and asymptomatic lesions …

An In Vitro Study Comparing The Conventional Step-Back Instrumentation Technique To A Combination Step-Back/Ultrasonic Technique, James A. Eberhardt

Loma Linda University Electronic Theses, Dissertations & Projects

Cleaning and shaping the root canal system is an important phase of endodontic therapy, and must be performed thoroughly and completely if successful root canal therapy is to be expected. A number of investigators have compared different methods of cleaning and shaping of the root canal system. The purpose of this study was to compare the effectiveness of the conventional step-back technique with that of a combination step-back/ultrasonic technique. This combination technique is a modification of the conventional step-back technique using an ultrasonic instrument alternately with hand instrumentation. Utilizing 40 canals from extracted human mandibular molar teeth with a curvature …

Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The pathogenesis of periapical lesions is the interaction of the oral flora with the existing host defenses. The role of bacteria has been established in endodontic disease but the contribution of the host defenses in periapical lesion formation is less clear. The purpose of this study was to compare periapical lesion development in immunosuppressed rats with that in normal rats. Thirty-five, eight-week old Sprague-Dawley rats were equally divided into seven groups. Groups 1, 2, and 3 were given weekly injections of Cytoxan, an immunosuppressive agent. Groups 4, 5, and 6 received no immunosuppressive therapy. Group 7 served as a control, …

Retrofilling Materials : The Effects Of Two Setting Times On The Degree Of Dye Leakage Of Retrograde Filling Materials, Robert K. Higa

Loma Linda University Electronic Theses, Dissertations & Projects

Sealing of the root canal system is usually accomplished by the conservative endodontic approach. Cases where it is impossible to treat nonsurgically are usually treated surgically by an apicoectomy and retrofill. There is a lot of controversy in the literature over which retrofilling material is closest to ideal. Presently, the most popular materials seem to be Amalgam, Super EBA, and IRM. For this reason, these materials were chosen for this study to evaluate the leakage potential at two different time intervals to see if setting time of the material had any influence on the amount of leakage.

Seventy extracted single …

Antibacterial Effects Of Various Endodontic Irrigants And Medicaments On Selected Anaerobic Bacteria, Patrick K. Ohara

Loma Linda University Electronic Theses, Dissertations & Projects

This study was undertaken to determine the antibacterial effects of various endodontic irrigants and medicaments against six selected anaerobic bacteria. In part 1, the organisms were mixed separately with dilutions of six irrigants in tubes containing fluid thioglycolate broth and allowed to remain in contact for specific time periods before being evaluated for growth. In part 2, the vapors of six medicaments were tested using agar plates streaked with the bacteria.

For part 1, the six irrigants were ranked as to their ability to inhibit bacterial growth. Statistical analysis showed that chlorhexidine and hydrogen peroxide were significantly more effective as …

The Role Of T Cells In The Pathogenesis Of Periapical Lesions, John B. Wallstrom

Loma Linda University Electronic Theses, Dissertations & Projects

The pulps of mandibular molars of 15 athymic and 15 conventional rats were surgically exposed and left open to their oral flora. Each group was divided into 3 subgroups of 5 animals each. The rats were sacrificed after their pulps were exposed for 2, 4, or 8 weeks. After fixing, decalcifying, and embedding, the specimens were sectioned and stained with H and E. They were then examined under a microscopic grid and quantified by percentages of surface areas of bone, connective tissue, bone marrow, intrabony spaces, periapical lesions, and numbers of osteoclasts. This was done using a DataVoice computerized data …

Concentration Of Leukotrienes B4 And C4 In Human Periradicular Lesions, Elisabetta Cotti

Loma Linda University Electronic Theses, Dissertations & Projects

The 5-lipoxygenase metabolites of arachidonic acid such as leukotrienes (LT) B₄ and C₄, are potent mediators of inflammation. The purpose of this investigation was to determine the concentrations of LTB₄ and LTC₄ in human periradicular lesions. Specimens from asymptomatic and symptomatic patients were obtained and immediately frozen in liquid nitrogen. Periradicular tissues from unerupted third molars as well as chronically inflamed gingival tissues were also obtained, frozen and were used as negative and positive controls respectively. The concentrations of LTB₄ and LTC₄ were determined by the reverse phase high pressure liquid chromatography. Representative …

The Concentration Of Prostaglandin E2 In Periradicular Lesions, Steve N. Mcnicholas

Loma Linda University Electronic Theses, Dissertations & Projects

Prostaglandins (PG) have been implicated in pathogenesis of periapical lesions. The purpose of this study was to determine the concentrations of PGE₂ in human periapical lesions. Periapical specimens from patients with clinical signs and symptoms of chronic and acute apical periodontitis were obtained and immediately frozen in liquid nitrogen. Periradicular tissues from unerupted third molars were frozen and used as controls. The concentration of PGE₂ was determined by radioimmunoassay. Low levels of PGE₂ were found in the control tissues as compared to those detected in chronic and acute lesions. A significantly higher level of PGE₂ was …

The Anatomical Relationship Of The Mandibular Canal And Related Structures In Immature And Mature Dried Mandibles, Dale Denio

Loma Linda University Electronic Theses, Dissertations & Projects

The anatomical relationship of the mandibular canal and related structures were examined in 29 dried human mandibles (21 mature and eight immature). First and second premolars and molars were sectioned in a buccal-lingual plane. The molars were separated into mesial and' distal sections. A total of 322 sections were examined according to age (immature or mature), left or right, and type of tooth/root. Thirteen measurements were taken of each section and the results were statistically analysed.

The results indicated no significant difference between the mean averages when comparing the 13 data points between the left and right side of mandibles …

A Transmission Electron Microscopy Study Of Early Changes In Hypoxic Pulps, Nah Nah Chen

Loma Linda University Electronic Theses, Dissertations & Projects

Early cellular changes in pulps whose blood supplies were severed were studied using transmission electron microscopy (TEM). Twenty-eight extracted teeth were divided into seven equal groups. Except for the 0 hour group, all other teeth were incubated in Tyrode solution at 37°C, after extraction. After 1/4, 1/2, 1, 2, 4, and 8 hours, teeth were split open and the pulps were processed for light and transmission electron microscopy and evaluated for cellular changes. Except for nuclear pyknosis in the 4 and 8 hour groups, light microscopic examination revealed very little changes when compared with that of TEM examination. With the …

The Determination Of Antibody Levels In Endodontic Patients Against Eleven Microorganisms Using Ifa And Elisa Techniques, William C. Payne

Loma Linda University Electronic Theses, Dissertations & Projects

Endodontic (root canal) infections are generally considered to be caused by the invasion of microorganisms which destroy pulp tissue and extend to the periapical region. No definitive study has identified a specific bacterium or group of bacteria as etiological agents. We quantitively measured antibodies present in the serum of 30 normal individuals and patients with either chronic (n = 30) or acute (n = 30) periapical lesions with the indirect fluorescent antibody (IFA) and enzyme-linked immunosorbent assay (ELISA) for IgG and IgM against 11 oral microorganisms routinely isolated from such lesions. The results were analyzed statistically. Analysis of variance of …

Effects Of Dentin Chips, Hydroxyapatite, And Demineralized Dentin As Apical Plugs, D. Wylie Brandell

Loma Linda University Electronic Theses, Dissertations & Projects

Two mm plugs of demineralized dentin, hydroxyapatite, or dentin chips were condensed into the apical perforations of 48 anterior teeth of eight adult cynamolgus monkeys. The remainder of the canals were obturated with gutta percha and Grossmans sealer using lateral condensation technique. The degree of hard tissue formation and inflammation was evaluated at three and six months. No significant changes were noted between various materials at three months. However, after six months, the samples with apical plugs of hydroxyapatite had more hard tissue formation and less inflammation than others.

Toxicity Of Root Canal Filling Materials On Hela Cells And Fibroblasts, Eldon P. Carman

Loma Linda University Electronic Theses, Dissertations & Projects

A study was undertaken to determine the concentration at which a sealer reaches a point of nontoxicity. An in vitro model utilizing HeLa cells and human fibroblasts was used to observe the effect of various concentrations of eight freshly mixed and eight set root canal sealers. Evaluation of toxicity was determined by cell survival which was measured by incorporation of ³H-thymidine into the nucleic acid components of each cell type used. Each dilution tested was allowed direct contact with the cells for 24 hours before toxicity evaluation. The results indicate that all sealers at concentrations presently used are cytotoxic …

The Effect Of Periapical Inflammation On Cellular Cementum : A Scanning Electron Microscope Study, Gary S. Yonemoto

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to obtain information on the morphologic changes that occur in cellular cementum exposed to periapical inflammation.

Ten single rooted human teeth were collected. There were five specimens of normal cellular cementum and five specimens of diseased cellular cementum, which had been exposed to periapical inflammation. Each specimen was fractured longitudinally through the apical foramen, leaving the organic component intact. The cross-sectional morphology of cellular cementum was then examined using an ARM Model 1000 scanning electron microscope. Energy dispersive x-ray spectrometry was also conducted on samples representative of the two test groups.

A methodology was …

The Effect Of Escherichia Coli Endotoxin On The Cat Periapical Tissues, Thomas G. Dwyer

Loma Linda University Electronic Theses, Dissertations & Projects

The periapical tissue reaction to three concentrations of endotoxin solutions and to a sterile saline control solution was examined in six adult cats. The maxillary and mandibular cuspids were isolated and the pulps extirpated with barbed broaches. The four solutions (1, 10, 100 μg/ml endotoxin, and saline) were then injected into the four prepared teeth for each cat and the access cavities sealed with IRM.

At two week intervals, two cats were sacrificed and the specimens removed, while the remaining animals were retreated as previously described. The block tissue sections were radiographed, fixed in 10% buffered formalin, and prepared for …

Stress Analysis Of Post And Crown Restorations Of Endodontically Treated Teeth, Ronald C. Hansen

Loma Linda University Electronic Theses, Dissertations & Projects

Forty-four similar sized maxillary lateral incisor teeth were randomly divided into four equal groups to test their resistance to fracture. Group 1 teeth were the controls, no treatment was done. Group 2 teeth consisted of endodontically treated teeth, restored with composite resin in the access opening. Group 3 teeth were endodontically treated and restored with a post and flat surface standardized aluminum crown. The teeth in Group 4 were endodontically treated and restored with a post and composite resin core buildup with a cast gold crown. The metal collar of gold incorporated 1.5 mm of tooth structure below the core …

Comparison Of Root Surfaces In Endodontic Lesions, Periodontic Lesions And Normal Human Teeth, Robert W. Hanson

Loma Linda University Electronic Theses, Dissertations & Projects

The healing potential of an endodontic lesion is usually greater than a periodontic lesion (Simon et al. 1972; Hiatt 1977). Periodontal regeneration places particular emphasis on the soft tissue-tooth interface (Stahl 1977). This interface was examined in fifteen extracted human teeth.

The teeth were divided into three groups: (1) periapical lesions, (2) periodontal lesions, and (3) healthy periodontal tissue. Criteria were established for each group. Freshly extracted human teeth meeting the criteria were fixed in gluteraldehyde or paraformaldehyde. The teeth were then selected for surface observation or cracked for cross sectional examination. The teeth were post fixed, dehydrated, and coated …

The Effect Of Endodontic Therapy On The Incidence Of Radiation Caries In Dogs, James A. Abbott

Loma Linda University Electronic Theses, Dissertations & Projects

Endodontic therapy was evaluated as a possible control or prevention modality of radiation type dental caries in dogs. Two adult male dogs with permanent dentitions had endodontic therapy performed on alternating teeth in each jaw. The nontreated teeth served as controls.

The dogs were irradiated with 7000 rad Cobalt-60 radiation fractionated over an eight week period. The dogs were killed at 60 and 182 days post-irradiation. The teeth were removed from the jaws and immersed in methylene blue dye, sectioned, and the dye penetration pattern photographed. Diffusion of the dye into the tooth structure was quantified and statistically analyzed.

A …

Ultrasonic Versus Hand Filing Of The Human Root Canal System, Howard W. Scholz Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

A comparison was made of ultrasonic filing versus hand filing using three solutions to flood the canals of 24 extracted human maxillary central incisors. A modified PR-30 Cavitron insert was used in a Cavitron 1010 unit for the ultrasonic filing. The clinical crown was removed with a diamond saw and water spray at the cemento-enamel junction. The two major groups were ultrasonic filing versus hand filing; the three subgroups were solution/solvents - 10% EDTA, 2.0% NaOCl, and distilled water.

After filing, the roots were grooved longitudinally with a high speed bur and cracked opened with a mallet and chisel. The …

Apical Closure Induction Using Bone Growth Factors And Mineral Trioxide Aggregate, Kenneth W. Tittle

Loma Linda University Electronic Theses, Dissertations & Projects

This study compared the ability of three different bone growth factor combinations with that of Ca(OH)₂ to stimulate apical closure as well as the effectiveness of Mineral Trioxide Aggregate (MTA) as an apical barrier. Fifty-six roots of second and fourth mandibular premolars of seven six- month old beagle dogs were used. Periradicular lesions were created over a four week period. The canals were cleaned and shaped and filled with Ca(OH)₂ for one week. They were then irrigated and received one of seven different treatments in a balanced design. Growth factors were placed in a carboxymethylcellulose carrier and delivered …

The Functional Stress Analysis Of Post Reinforcement, Robert V. Bravin

Loma Linda University Electronic Theses, Dissertations & Projects

Research was undertaken in order to functionally test the reinforcement capabilities of several commonly used, standard manufactured posts. One hundred and ten maxillary lateral incisors were mounted in plastic, reinforced with the posts at different levels, and then restored with standardized crowns. These teeth along with control groups, were then placed in a custom, mounting jig which properly positioned them for the stress testing. The forces required for fracturing these teeth were recorded and subsequently analyzed.

The statistical analysis of the experimental results demonstrated that posts do not reinforce teeth as supposed; they may, in fact, weaken them. Analysis also …

Histology Of Apical Tissue : A Comparative Study Of Sargenti Formula, Short Vs. Overfill, James G. Schulze

Loma Linda University Electronic Theses, Dissertations & Projects

Four Stump-tail monkeys (Macaca spiciosa) were used for this study to analyze, on a cellular level, the apical tissue of teeth overfilled versus teeth filled short 1-3 mm. of the radiographic apex with the Sargenti formula. In each animal four incisors were filled short and four incisors were overfilled. A final sample size consisted of 28 teeth. The time periods ranged from 48 hours to 120 days. After analysis of the histology it can be stated that the teeth filled short showed no inflammation to moderate inflammation in the periapical tissues. In teeth overfilled there was a range from moderate …

Determination Of Lead Content In Apical Tissue Following Root Canal Obturation With Sargenti's Formula, G. Merle Hickok

Loma Linda University Electronic Theses, Dissertations & Projects

Four Stump-tail monkeys were used to help determine if the lead in Sargenti's formula diffuses out into the apical tissue while confined entirely within the root canal. In each animal two teeth were filled with Sargenti's formula 1-2 millimeters short of the radiographic apex, and two teeth were filled with gutta percha and Proco-Sol sealer for controls, making a total sample size of sixteen. The time ranged from 48 hours to 120 days. Lead analysis using the spectrophotometric method showed a higher lead content in the teeth filled with Sargenti's formula than with the gutta percha controls.

A Clinical Comparison Of The Effectiveness Of Two Intracanal Medicaments, Xp-7/Prednisolone And 1% Pcp/Prednisolone, In Reduction And Duration Of Post-Treatment Pain, Kenneth G. Whitnack

Loma Linda University Electronic Theses, Dissertations & Projects

This study was undertaken to determine which intracanal medication, 1% aqueous parachlorophenol with prednisolone or XP-7 with prednisolone was the most effective in reducing the severity and duration of post-treatment pain following initial, conventional endodontic therapy. The investigation was conducted by five endodontists in their private offices and utilized a double-blind technique.

The postoperative reactions of 343 patients were examined statistically. It was shown that there was no statistically significant difference in the reduction or duration of post-treatment pain with either drug. Other factors such as sex, age, location of tooth and presence of a radiographic lesion were statistically significant …

An Evaluation Of The Cytotoxicity Of Root Canal Filling Materials On Tissue Culture Cells In Vitro: Grossman's Sealer, N2 Permanent, Rickert's Sealer, And Cavit, Donald D. Antrim

Loma Linda University Electronic Theses, Dissertations & Projects

An in vitro study using radioactively-labeled tissue culture cells was conducted over a seven-month period on Grossman's sealer, Rickert's sealer, N₂ Permanent, and Cavit to determine the lasting and relative tissue toxicity of these materials.

From this study it was observed that all materials possess lasting tissue toxicity. When relative toxicity is considered, Grossman's is the most toxic, followed by N₂, Rickert's and Cavit in descending order of toxicity. Both Grossman's and N₂ would be considered highly toxic, with Rickert's displaying moderate toxicity. Cavit would be considered mild to moderate in toxicity.

The use of radioactively-labeled …

Bone Regeneration Over Submerged Dental Roots In Dogs, Roger Lee Plata

Loma Linda University Electronic Theses, Dissertations & Projects

Nonendodontically treated roots were submerged 1.5 to 2.0 mm. below the alveolar crest in three dogs. Twelve roots were treated in this manner. Regeneration of alveolar bone can be seen in three weeks with complete bone coverage in five weeks. A complete lamina dura can be seen around the amputated roots.

Bone failed to regenerate over two of the twelve roots. In one case there was delayed healing due to the early loss of some sutures. A sinus tract developed connecting the oral environment with the contents of the pulp. This led to bone resorption and a necrotic pulp. In …

Histological Comparison Of Human Pulpal Tissue Reactions After Vital Partial Pulpectomies Using N-2, Dycal And Zoe Paste, David P. Clark

Loma Linda University Electronic Theses, Dissertations & Projects

A histological comparison of forty-four human teeth in which vital partial pulpectomies were performed, and the pulp stumps covered with dycal, N-2 and ZOE was carried out. The time interval at which the teeth were extracted for study was ten, twelve and fourteen weeks. These teeth were on patients twelve through seventeen years of age and were to he extracted for orthodontic purposes. The teeth were caries free, vital and asymptomatic. The percent retaining vital tissue, time intervals and type of paste were as follows:

• 14 week, dycal 75%
• 14 week, N-2 100%
• 12 week, ZOE 30%
• 12 week, N-2 …

Histologic Comparison Of Apical Tissue Response To Endodontic Overfills With Gutta Percha And Grossman's Sealer Vs. Sargenti Method (N₂), Donald L. Brewer

Loma Linda University Electronic Theses, Dissertations & Projects

This study compared endodontic overfills of N₂ and gutta percha-Grossman's Sealer from a histopathological basis. The study employed four male rhesus monkeys and a sample of 31 teeth.

The most obvious difference between the samples filled with N₂ and the gutta percha-Grossman's Sealer samples was the recurring presence of ankylosis in the N₂-treated teeth. Results also included bone necrosis, inflammation and root and bone resorption.

The N₂ samples were considered to have evidenced greater violence of reaction apically.

The Lasting Antimicrobial Qualities Of Three Root Canal Sealing Materials : Grossman's Sealer, Rickert's Sealer, And N2 Permanent, Lee R. Ingersoll

Loma Linda University Electronic Theses, Dissertations & Projects

An in vitro study using polyethylene tubes filled with Grossman's sealer, Rickert's sealer, and N2 permanent was conducted over a six month period in an effort to determine their lasting antimicrobial properties against eight different microorganisms.

From the study it was observed that N2 permanent possesses a long-lasting antimicrobial effect, but this effect appears to diminish greatly with time. Further investigation is needed to determine whether or not the effect is actually permanent in nature. The N2 permanent was also shown to have broader antimicrobial effectiveness against the eight microorganisms tested. N2 permanent produced zones of inhibition against five of …