Chapter 8 : Experimental Studies of Root Canal Therapy for Infected Nonvital Permanent Teeth with Incompletely Formed Apices

A total of 160 root canals in 90 teeth with incompletely formed roots of puppies were prepared for infected root canal therapy. The experimental group was treated with Vitapex and the control group was treated with calcium hydroxide-CMCP paste root canal filling material. Histopathological sections from decalcified specimens were prepared after observation periods of 30, 60, 120 and 180 days. In addition, 24 root canals in 16 teeth were treated with Vitapex on the opposite side with sound teeth and subjected to tetracycline administration. Observations were carried out by contact microradiography and tetracycline labeling and resulted in the following conclusions. 1: Almost no root growth was observed using both root canal filling materials, and the addition of newly-formed hard tissue was observed close to the root apical foramen involved. 2: The addition of hard tissue after root canal filling was thought to be primarily by cementum. 3: A greater amount of hard tissue formation resulting in closure of the apex and a more favorable outcome was observed in the control group than in the experimental group. 4: The control group had a higher percentage of hard tissue formation outside the root apex close to the root tip than did the experimental group. 5: The experimental group showed good results in each observation period. The control group showed better results with a shorter observation period than did the experimental group, but in longer observation periods, tended to decrease in cases with poor results. 6: Undecalcified specimens were examined using contact microradiography and tetracycline labeling. In the experimental group, the addition of newly-formed hard tissue was observed close to the apical foramen near the root tip formed during the course of treatment. Normal root formation in the dental arch was observed in all samples in the experimental and control groups.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Chapter 6 : Histopathological Studies of Pulpectomy in the Deciduous Teeth of Dogs

A study was performed to examine the impact of resorbable root canal filling material, Vitapex, containing calcium hydroxide and iodoform, on the physiological resorption of its roots, succedaneous permanent tooth buds and periodontal tissues. A total of 14 puppies aged 2-5 months were used; teeth were anesthetized, pulps were extirpated and immediate root canal filling was performed. These procedures were carried out in 53 deciduous teeth with 81 root canals, and contralateral intact teeth were used as controls. The animals were bred for 5 to 60 days and were tracked with radiographical and histological examinations. Results obtained were the following: 1: The form of healing observed after the experimental procedures was divided into 2 groups: those healed either by remaining vital pulp tissue or by the periodontal ligament, with 17 and 29 cases, respectively. 2: The resorption of root canal filling material and the physiological root resorption were almost the same in the majority of cases. 3: The rate of physiological root resorption in the experimental group was slightly delayed compared to that of the control group. 4: The remaining pulp tissue lesions, either in short or long term cases, comprised 5 cases of congestion, 3 cases of hemorrhage, 5 cases of mild inflammation, 11 cases of purulent inflammation, and 1 case of atrophy. 5: Periapical lesions, either in short or long term cases, comprised 6 cases with congestion, 12 cases with mild inflammation, 17 cases with purulent inflammation and 7 cases with pathological alveolar bone resorption. 6: In most cases, the lesions did not significantly affect the permanent tooth buds, except for 6 of 81 cases. 7: Pathological grades obtained in this experiment, in a total of 81 cases, were good in 41 cases (50.6%), fair in 20 cases (24.7%) and a failure in 20 cases (24.7%). 8: The best pathological grades after the experimental procedure were obtained in cases in which the root canal filling material was limited within the canal itself (flush) and in those cases which were underfilled. Overextension of root canal filling should be avoided as much as possible. 9: The relationship between root status and pathological grades showed a slightly lower incidence and favorable results with physiological root resorption compared to those without physiological root resorption. 10: In this study, the use of Vitapex for immediate root canal filling after pulp extirpation in canine deciduous teeth produced good results. Vitality of the remaining pulp and periodontal tissue was restored with subsequent physiological root resorption and without adverse effect on succedaneous permanent tooth buds.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Visual hallucinations in dementia with Lewy bodies originate from necrosis of characteristic neurons and connections in three-module perception model

Mathematical and computational approaches were used to investigate dementia with Lewy bodies (DLB), in which recurrent complex visual hallucinations (RCVH) is a very characteristic symptom. Beginning with interpretative analyses of pathological symptoms of patients with RCVH-DLB in comparison with the veridical perceptions of normal subjects, we constructed a three-module scenario concerning function giving rise to perception. The three modules were the visual input module, the memory module, and the perceiving module. Each module interacts with the others, and veridical perceptions were regarded as a certain convergence to one of the perceiving attractors sustained by self-consistent collective fields among the modules. Once a rather large but inhomogeneously distributed area of necrotic neurons and dysfunctional synaptic connections developed due to network disease, causing irreversible damage, then bottom-up information from the input module to both the memory and perceiving modules were severely impaired. These changes made the collective fields unstable and caused transient emergence of mismatched perceiving attractors. This may account for the reason why DLB patients see things that are not there. With the use of our computational model and experiments, the scenario was recreated with complex bifurcation phenomena associated with the destabilization of collective field dynamics in very high-dimensional state space

Bond Characterization in Very High Power Ultrasonic Additive Manufacturing

Solid parts were produced by Very High Power Ultrasonic Additive Manufacturing (VHP-UAM) at room temperature using 150 μm thick tapes of 6061 aluminum and 110 copper alloys. Processing was done at 20 kHz frequency over a range of parameters (26 –36 μm vibration amplitude, 5.6 – 6.7 kN normal force, and 30.5 - 35.5 mm/s travel speed). Softening of materials (up to about 14% in 6061 Al and 23% in 110 Cu) was noted facilitating enhanced plastic flow and a reduction in interfacial voids. Evolution of fine recrystallized grains (0.3-4 μm in 6061 Al and 0.3-10 μm in 110 Cu) from an initial coarser grain structure (up to 8 μm in 6061 Al and 25 μm in Cu) was observed at the build interface regions. Bonding between layers in both materials seems to have occurred by dynamic recrystallization and movement of grain boundaries across the interface. The energy required for the above physical processes is derived from interfacial adiabatic plastic deformation heating.Mechanical Engineerin

Chapter 7 : Clinical and Radiographic Examinations of Pulpectomy in Deciduous Teeth

Clinical and radiographic examinations were done on 163 deciduous teeth treated with a root canal filling material called Vitapex, which contains calcium hydroxide and iodoform. Anesthesia was administered, followed by pulp extirpation and immediate root canal filling, with observation for 5 to 1307 days. The following results were obtained. 1: Excessive bleeding during pulp extirpation seemed to adversely affect the overall clinical and radiographic results. The poor clinical condition of the pulp resulted in a higher incidence of poor results based on radiographs. 2: Deciduous teeth are susceptible to overfilling after a certain period due to root resorption. A higher incidence of good pathological scores was obtained when the root canal filling was flush, not overfilled. Radiographs confirmed resorption of excess root canal filling material in all cases. 3: During the observation period, root canal filling materials were in a stable condition and only few roots exhibited resorption. Root resorption occurred earlier or at the same time as the resorption of root canal filling material. 4: During the observation period, eruption of the succeeding permanent teeth was observed in 18 cases. In 12 out of 18 cases, eruption of the succeeding tooth did not occur at the same time as on the contralateral side (control). In 6 out of 12 cases, eruption of the succeeding permanent tooth was earlier than on the contralateral side but in 4 out of 12 cases, a delay in the replacement was observed. Also, 2 cases were replaced almost immediately. 5: During the observation period, pathological root resorption was observed in cases where root canal filling material was rapidly resorbed. 6: Until the last observation day, 127 out of 163 cases (77.9%) showed no clinical discomfort or adverse radiographic findings and only 36 out of 163 cases (22.1%) showed some discomfort. 7: Signs and symptoms observed in the study were the following: 5 cases of spontaneous pain, 3 cases of pain during mastication, 10 cases of pain on percussion, 3 cases of gingival swelling, 1 case of redness, 1 case of tenderness, 3 cases of fistula and 3 cases of drainage. Discomfort was felt from the 1st to 3rd day after treatment and was mostly of a mild degree. 8: Radiographic findings of those with clinical discomfort were the following: 2 cases with loss of lamina dura, 12 cases with incomplete resorption, 8 cases with root resorption and 5 cases with pathological lesion. 9: In 36 cases with clinical discomfort and adverse radiographic findings, 12 cases (33.3%) had clinical discomfort only, 17 cases (47.2%) had clinical discomfort associated with adverse radiographic findings and 7 cases (19.5%) were asymptomatic but with adverse radiographic findings. Adverse radiographic findings were observed in 13 out of 91 cases (14.3%) in anterior and 23 out of 72 cases (31. 9%) in posterior teeth. The clinical diagnosis of cases with adverse radiographic findings was observed in the most infectious pulpitis particularly acute suppurative pulpitis and chronic hyperplastic pulpitis. 10: The overall clinical and radiographic results obtained in the study were the following: out of 163 cases, 127 obtained good results (77.9%) and 25 cases were fair (15.3%) for a total of 93. 2% had satisfactory results. Only 11 cases had poor results (6. 8%). In 151 cases with stable periodontal tissue condition from the radiograph, 117 cases obtained good results (77. 5%), 23 cases were fair (15. 2%) and 11 cases were poor (7. 3%). Resorption of about 1/4 to 2/3 of the root occurred in 12 cases, in which 10 cases obtained good results (83.3%), 2 cases were fair (16.7%) and none of the cases was classified as poor. Root canal filling immediately after anesthesia and pulp extirpation in cases with advanced root resorption was thought to be significant. 11: There was no change in the condition of the root in 92 cases until the last observation day. In 92 cases, 72 cases obtained good results (78.3%), 9 cases were fair (9.8%) and 11 cases were poor (11. 9%). The remainder of the 59 cases with root resorption became stable within the observation period. In 59 cases, 45 cases obtained good results (76.3%), 14 cases were fair (23.7%) and no case was classified as poor. Vitapex employed in root canal filling of deciduous teeth mostly did not induce clinical signs and symptoms, and adverse radiographic findings as well as affecting physiological root resorption confirming that this is an excellent root canal filling material.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

Chapter 9 : Clinical and Radiographic Observation of Permanent Teeth with Incompletely Formed Roots after Root Canal Therapy

A total of 33 teeth with 66 root canals were clinically diagnosed as irreversible pulpitis, and 38 teeth with 53 canals were diagnosed as apical periodontitis. Those 71 teeth had 119 root canals, with incompletely formed roots, and they underwent root canal therapy and filling using a formulation of calcium hydroxide and iodoform called Vitapex and were clinically observed for 30 to 1312 days. The following are the results and conclusions. 1: After root canal therapy, the condition of the root canal filling material was determined by radiograph In 66 root canals with irreversible pulpitis, 16 cases were overfilled, 11 cases were flush and 39 cases were underfilled. In 53 cases with apical periodontitis, 28 cases were overfilled, 10 cases were flush and 15 cases were underfilled. 2: Clinical discomfort was experienced in 10 cases with irreversible pulpitis and in 3 cases with apical periodontitis. However, most of the discomfort was of a mild degree and disappeared within a week. 3: At the last observation, a high frequency of closure of the root apex was observed by radiograph. Cases with apical periodontitis tend to have a slight delay in inducing closure of the root apex compared with cases with irreversible pulpitis. However, after 540 days, closure of the root apex was observed in all cases. 4: Clinical and radiographic findings show that in 33 cases with irreversible pulpitis, 23 cases were good, 9 cases were fair and 1 case was poor. On the other hand, in 38 cases with apical periodontitis, 35 cases were good, 2 cases were fair and 1 case was poor.Editor, Toshiyuki KawakamiLanguage Editor, David M Carlsonviii, 232 p. ill. (some col.

The Pathogenic Factors from Oral Streptococci for Systemic Diseases

The oral cavity is suggested as the reservoir of bacterial infection, and the oral and pharyngeal biofilms formed by oral bacterial flora, which is comprised of over 700 microbial species, have been found to be associated with systemic conditions. Almost all oral microorganisms are non-pathogenic opportunistic commensals to maintain oral health condition and defend against pathogenic microorganisms. However, oral Streptococci, the first microorganisms to colonize oral surfaces and the dominant microorganisms in the human mouth, has recently gained attention as the pathogens of various systemic diseases, such as infective endocarditis, purulent infections, brain hemorrhage, intestinal inflammation, and autoimmune diseases, as well as bacteremia. As pathogenic factors from oral Streptococci, extracellular polymeric substances, toxins, proteins and nucleic acids as well as vesicles, which secrete these components outside of bacterial cells in biofilm, have been reported. Therefore, it is necessary to consider that the relevance of these pathogenic factors to systemic diseases and also vaccine candidates to protect infectious diseases caused by Streptococci. This review article focuses on the mechanistic links among pathogenic factors from oral Streptococci, inflammation, and systemic diseases to provide the current understanding of oral biofilm infections based on biofilm and widespread systemic diseases

Successful Treatment of Staphylococcus schleiferi Infection after Aortic Arch Repair: In Situ Aortic Arch Replacement and Domino Reconstruction of the Debranching Graft using Autologous Iliac Artery

A 62-year-old Japanese male presented with graft infection by Staphylococcus schleiferi 50 days after debranching of the left subclavian artery and frozen elephant trunk repair for the entry closure of a Stanford type B aortic dissection. The graft was removed, and the patient was successfully treated using in situ reconstruction of the arch with omental flap coverage, removal of the debranching graft, autologous iliac artery grafting, and longterm antibiotics. Domino reconstruction of the infected debranching graft using autologous external iliac artery and a Dacron graft can thus be a good option in similar cases

Autonomic nervous alterations associated with daily level of fatigue

<p>Abstract</p> <p>Background</p> <p>Fatigue is a common symptom in both sick and healthy people. We examined autonomic nervous alterations associated with fatigue to clarify the mechanisms underlying fatigue.</p> <p>Methods</p> <p>The study group consisted of 19 healthy participants who performed a 2-back test for 30 min as a fatigue-inducing mental task session. Before and after the session, they completed the advanced trail making test (ATMT) for 30 min for mental fatigue evaluation, subjective scales to measure fatigue sensation, and underwent electrocardiography to allow assessment of autonomic nerve activities.</p> <p>Results</p> <p>After the fatigue-inducing task, the total error counts on the ATMT tended to increase (<it>P </it>= 0.076); the ATMT for total trial counts (<it>P </it>= 0.001), the subjective level of fatigue (<it>P </it>< 0.001), and the % low-frequency power (%LF) (<it>P </it>= 0.035) increased significantly; and the % high-frequency power (%HF) decreased compared with before the fatigue-inducing task although this did not reach the statistical significance (<it>P </it>= 0.170). Although LF measured in absolute units did not change significantly before and after the fatigue-inducing task (<it>P </it>= 0.771), and HF measured in absolute units decreased after the task (<it>P </it>= 0.020). The %LF and LF/HF ratio were positively associated with the daily level of fatigue evaluated using Chalder's fatigue scale. In addition, %HF was negatively associated with the fatigue score.</p> <p>Conclusions</p> <p>Increased sympathetic activity and decreased parasympathetic activity may be characteristic features of both acute and daily levels of fatigue. Our findings provide new perspectives on the mechanisms underlying fatigue.</p