Indiana University-Purdue University Indianapolis (IUPUI)

Indiana University-Purdue University Indianapolis (IUPUI) / A study was conducted on the effects in a rhesus monkey of increasing the surface area of pulpal tissue available for revascularisation and regeneration of nerves after replantation of permanent teeth. Four teeth were replanted and used for controls, including two with incomplete apical development. Twelve teeth with completed apical development were replanted immediately after apical modification to increase the surface area of exposed pulp. The technique consisted of creating a facial and lingual groove in the apical region and exposing additional pulpal tissue. Radiographs were taken periodically and the replanted teeth were stable during the study period. The monkey was sacrificed after 93 days. The first hypothesis, that the apically modified teeth would sustain a healthy periodontium clinically for a period of ninety days, was disproved. Histological sections of the teeth and their supporting tissues showed varying amounts of root resorption and ankylosis. All of the apically modified teeth showed pulp necrosis, while three of the four control teeth had reestablished blood and vascular supplies and appeared vital. Ingrowth of granulation tissue was seen in the replanted teeth with pulp necrosis including one control tooth which had failed to revascularize. The second hypothesis, that the apically modified teeth would demonstrate significantly more apical revascularisation and nerve regeneration than the control teeth, was also disproved. In conclusion, the apical modification technique as performed to increase the area available for regeneration of nerves and vessels was not a success. As expected, however, immediate replantation of avulsed teeth resulted in reestablishment of periodontal membrane attachments.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: Increasing prevalence of dental erosion has been observed in many countries, in both children and adults. This condition is often associated with softening of the dental surface by acid exposure, which may lead to severe and irreversible damage. The use of fluoride, pit and fissure sealants, dental adhesives and more recently a resin infiltrant has been suggested to manage dental erosion. Objective: To compare the protective effect of a resin infiltrant and other resin-based materials against dental erosion/toothbrushing abrasion in vitro. Materials and methods: Bovine enamel and dentin slabs were prepared, embedded, flattened and polished. Dental erosion lesions were created using 0.01 M of hydrochloric acid (pH 2.3 for 30 sec) and treated with resin-based materials (HS: Helioseal pit and fissure sealant; SP: Seal and Protect dentin 78 sealant, and IC: Icon resin infiltrant) or fluoride varnish (FV: Duraphat). A no-treatment group represented the negative control (C). The specimens were subjected to an erosion-abrasion cycling model for a total of 10 days. Each cycling day consisted of 2 min immersion in 0.01M HCl, at room temperature, for 4 times; and toothbrushing with either of the abrasive suspensions (low and high, as previously determined by the radioactive dentin abrasivity method). Enamel and dentin surfaces were scanned at baseline, after treatment, at 5 days and at 10 days using an optical profilometer. Surface change (loss/gain) was determined by subtracting the treated area from the reference (protected) areas. Significance level of 5% was adopted for the statistical analysis. Results: No differences were found among groups at baseline, regardless of substrate. After treatment, surface deposition was found for all test groups except for IC, which did not differ from C. For enamel, at day 5, FV, HS and SP had less surface loss than C and IC (p<0.0008), which did not differ from each other (p=1.00). At day 10, similar trend was observed except for FV, which showed surface loss similar to C, when brushed with high abrasive suspension. High abrasive caused more surface loss than low abrasive only for C at day 5 (p=0.0117) and 10 (p=0.0162). For dentin, at day 5, FV, HS and SP had less surface loss than C and IC (p≤0.0001), which did not differ from each other (p=1.00). At day 10, HS and SP had less surface loss than C, IC, and FV (p<0.0001), and FV had less surface loss than C for low abrasive (p=0.0009). Overall, high abrasive had significantly more surface loss than low abrasive at 10 days (p=0.0280). Conclusion: HS was the most effective material protecting enamel and dentin from erosion-abrasion, followed by SP. FV offered limited protection, while no benefit was observed for resin infitrant IC.

Indiana University-Purdue University Indianapolis (IUPUI) / The effect of untimely loss of deciduous molars on the eruption and development of succedaneous premolars was serially studied in eight children in the mixed dentition stage from 45 degree cephalometric films made at three and six month intervals. Each child had one mandibular deciduous molar removed for reasons other than periapical infection and a lingual arch space maintainer provided. The premolar beneath the extracted molar served as the study tooth; its antimere, as the control tooth. Eruptive movement was measured as the distance between the cusp-tip of a premolar on a superpositioned initial tracing and the corresponding cusp-tip on successive films. Antero-posterior movement of premolars was evaluated on a composite tracing along grid lines oriented to a common base line. Tooth formation was assessed by the increase in root length on successive films. Variation was found in the amounts of eruptive movement and root growth during a three month interval, for all premolars within the sample, within an individual and for a single tooth. In no case did a control tooth erupt more than a study tooth in a given interval. The initial effect of deciduous molar loss on eruptive movement in this study appeared to be accelerative. Tooth development was not found to be effected. While moderate correlation was found between eruptive movement and root growth for all premolars, one process did not appear to be solely dependent on the other. A posterior component of eruptive movement was occasionally demonstrated but was not related to the extraction. The clinical value of this study is limited due to its small sample and short duration. Longer and more comprehensive studies of this problem are recommended.

Indiana University-Purdue University Indianapolis (IUPUI) / This study evaluated the effectiveness of bleaching tetracycline-stained teeth by measuring the loss of fluorescent intensity from teeth that were bleached. Nineteen male New Zealand white rabbits, with 58 incisors stained with oxytetracycline and 16 incisors as unstained controls, were used. Three rabbits were sacrificed to determine whether the tetracycline stain was comparable between incisors in the same jaw. Of the remaining 16 animals, 6 were bleached once and 10 were bleached twice. One maxillary and one mandibular incisor were bleached in each jaw with 30 percent hydrogen peroxide and heat for ten minutes per tooth; the other incisors were protected with a rubber dam. The animals were sacrificed 24 hours after the last bleach. The fluorescent intensity of 374 select ground sections 100 ± 5 microns thick from the incisal, middle and gingival thirds of the teeth were measured with an ultraviolet light microscope coupled to a television electronic measurement system. These measurements were statistically analyzed by t-test, and observations correlated. The dentin of tetracycline-stained maxillary incisors which were bleached twice and the dentin in the incisal one-third of the mandibular incisors which were bleached twice had a significantly (P ≤ 0.001, P ≤ 0.005) lower tetracycline fluorescent intensity than the dentin of unbleached tetracycline-stained teeth. The greatest loss of fluorescent intensity of tetracycline occurred in dentin closest to the dentino-enamel junction and varied from about 150 to 350 microns from the outer enamel surface. Clinical Kodachromes indicate that the loss of tetracycline pigment is associated with the loss of tetracycline fluorescence; The ground sections showed that the tetracycline fluorescence was never totally removed by two bleaches.

The study deals with the question of minor oral surgery procedures, dental extractions especially, in patients suffering from haemocoagulation disorder. The aim of this study was 1) the clinical attestation of the risk of bleeding that may follow the dental extraction in patients with non-interrupted oral administration of drugs with the anticoagulant and antiplatelet effects and 2) suggestion of the schedules of surgical procedures suitable for this kind of patients and for the realization in the standard dental office. The opening theoretical part analyses the principle of haemocoagulation, the surway of individual inherited and acquired bleeding disorders and the main principles of treatment of bleeding patients in dental offices with the emphasis on the local security of the surgical wound. In the proper study we present the observation and evaluation of bleeding complications after the standard dental extractions in 3 groups of persons (age range, 19 to 93 years). In all patients, one or more extractions were performed. 99 patients were treated with oral anticoagulant therapy without any interruption and underwent 199 extractions. 149 patients, treated with antiplatelet therapy (acetylsalicylic acid) without interruption, underwent 347 extractions. 160 healthy subjects with 316 extractions served as a...

The purpose of this study was to isolate a relatively pure population of granules from the DF and SR of 7 day old rats and characterize them biochemically. If this could be accomplished, the next step was to determine if the granule proteins may play a role in tooth eruption.

Indiana University-Purdue University Indianapolis (IUPUI) / Tooth mobility as it relates to orthodontics has not been thoroughly explored. The immediate aim of this project was to develop and test instrumentation to measure both tooth mobility and instantaneous centers of rotation under forces applied perpendicular to the tooth long axis. Two identical dial micrometers were selected and modified to allow variability in range, calibration, and contact pressure. All forces were delivered by mechanical force meters. A holding device was constructed to permit rigid positioning of a micrometer perpendicular to the long axis of any tooth in the arch and measure mobility at one point on the tooth. With an applied force of 500 gm., mobility measurements were made with the instrument on 44 teeth of six orthodontic patients. By repeating the analyses the instrument reproducibility was demonstrated. The pattern of tooth movement to applied force was explored and related to possible stress levels in tipping movements. A second holding device allowed both micrometers to contact a dental extension which was fixed to a maxillary central incisor. An incisor from each of four preorthodontic and two postorthodontic patients was analyzed. Over 200 clinical centers of rotation were calculated from measurements of tooth movements at two points on the tooth's long axis. Results from the first three patients were erratic. The rotation centers of the last three patients generally remained at midroot and also near the theoretical center of the tooth for all forces applied over 50 gm. More comprehensive studies on tooth mobility are recommended.

Indiana University-Purdue University Indianapolis (IUPUI) / This study was undertaken to histologically evaluate orthodontic tooth movement in hypothyroid and in normal Macaque speciosa monkeys. The experimental animals were rendered hypothyroid by radiosurgically altering the thyroid gland. A clinically acceptable orthodontic force was delivered to the anterior teeth of the monkeys. After the desired movement, a histologic investigation was made to correlate tissue responses with pressure, tension and root resorption. There was no significant difference among the three experimental animals. Likewise, there was no significant difference between the control animal and the three experimental animals. Osteoblastic and osteoclastic activity occurred to a comparable degree in both the experimental and control animals and was within normal limits for the amount of orthodontic tooth movement achieved. Root resorption was evident in both orthodontically treated and non-treated teeth in both the experimental and control animals. The root resorption observed was not significantly different, quantitatively or strategically, between the experimental and the control animals. Repair of root resorption was evident in both the experimental and control animals.

Indiana University-Purdue University Indianapolis (IUPUI) / It has been debated as to whether teeth may actually be intruded in their alveoli. This study was designed to measure the intrusive movement and histologic response of specific teeth to a known intrusive force. Four Macaque speciosa monkeys were used. The animals corresponded in age to a 12-14 year old human being. Intrusive forces of either 10, 50, 100, or 300 grams were placed on the maxillary first premolars; each force value was held constant during the duration of the experiment, which was 60 days. Maxillary first molars were used as anchorage. Cephalometric headplates proved that all force values were capable of giving intrusion. The 50 gram forces, however, gave the most efficient intrusion. Histologic sections were made on all experimental teeth. 300 and 100 gram forces gave excessive root resorption but the 50 and 10 gram force values elicited only slight root resorption. Root resorption seemed to be directly related to excessive force. The amount of intrusion was not related to a loss of root structure. Bone resorption appeared to allow the intrusion of teeth with minimal tissue damage if proper force values were used.