Showing papers in "Acta Odontologica Scandinavica in 1979"
TL;DR: It is concluded that patients with osseointegrated oral implant bridges have a masticatory muscle function equal to or approaching that of patients with natural teeth, or with tooth-supported bridges, with the same number of chewing units as the OIB-patients.
Abstract: The function of the masticatory system of 13 women, aged 42-59 years, with osseointegrated oral implant bridges (OIB) made within the last seven years was compared with that of 10 matched dentate controls by means of a questionnaire, clinical examination, bite force measurements and electromyographic recordings of biting and of postural muscle activity. Both groups were satisfied with their masticatory capacity according to the questionnaire. The clinically determined state of the masticatory system, as judged from the clinical dysfunction index, was normal in both groups. Three levels of bite force 1) gentle biting, 2) biting as when chewing and 3) maximal biting, were recorded with a bite force apparatus and electromyographically. There was no statistically significant difference between the groups at any level of bite force for any of the methods of registration. Nor was there any difference of the two groups in the activity of the masticatory muscles with the mandible in the postural position. It is concluded that patients with osseointegrated oral implant bridges have a masticatory muscle function equal to or approaching that of patients with natural teeth, or with tooth-supported bridges, with the same number of chewing units as the OIB-patients.
181 citations
TL;DR: Full agreement was observed between the findings from the culturing and histobacteriological examinations concerning presence or absence of microorganisms at the pulpal wall in all 14 teeth.
Abstract: The occurrence, viability and identification of the microbial flora under composite fillings using an anaerobic technique were studied Class V cavities were prepared on clinically healthy buccal surfaces of 7 contralateral pairs of premolars in children 11--15 years of age After preparation, rubber dam was applied and one cavity in each pair of teeth was washed with water blasted dry with air and filled with Adaptic The other cavity was washed with a cavity cleaner (Tubulicid) and a cavity liner (Tubulitec) was applicated prior to filling with Adaptic The teeth were extracted after 4--6 weeks Under anerobic conditions the tooth crown was split From one half samples were taken from the pulpal wall under the filling and cultured on blood agar and in broth medium The other half was examined with histobacteriological technique No growth occurred in cultures from lined cavities but in 6 of the 7 unlined cavities Full agreement was observed between the findings from the culturing and histobacteriological examinations concerning presence or absence of microorganisms at the pulpal wall in all 14 teeth The flora was mixed Gram-positive bacteria, mainly Streptococcus and Actinomyces, dominated over gram-negative bacteria including Veillonella, Fusobacterium, Campylobacter and Selenomonas The composition of the flora was more similar to that observed in dental plaque than that found in carious dentin or in saliva in other studies
74 citations
TL;DR: The relationship between traumatic injuries to upper permanent incisors and incisal overjet, with special reference to the age at which the trauma occurred, was studied in a sample of 1437 orthodontically untreated children aged 7--16 years.
Abstract: The relationship between traumatic injuries to upper permanent incisors and incisal overjet, with special reference to the age at which the trauma occurred, was studied in a sample of 1437 orthodontically untreated children aged 7–16 years. Traumatic injuries to hard dental tissues and exarticulations of teeth were recorded. Before 10 years of age, the increase of the prevalence rates was most rapid in the extreme (> 6 mm) overjet group in both sexes; the ratios between the extreme and normal (0–3 mm) overjet groups being 6.5/1 in girls and 5.0/1 in boys. According to the estimate, about 50 % of the girls and 70 % of the boys in this overjet group with injuries were affected before the age of 10 years.
65 citations
TL;DR: The frequency of traumatic injuries to permanent incisors was studied in a sample of 1614 children from the city of Lahti in Southern Finland, finding a rapid growth in the prevalence rates at the ages of 9--11 years, at which the estimated mean annual incidence was about 5% in girls and 7% in boys.
Abstract: The frequency of traumatic injuries to permanent incisors was studied in a sample of 1614 children from the city of Lahti in Southern Finland. The children, 801 girls and 813 boys, ranged in age from 6 to 16 years. Injuries to hard dental tissues and exarticulations of teeth were recorded. The prevalence of injuries was 19.8%-14.6% in girls and 25.0% in boys. A rapid growth in the prevalence rates was found at the ages of 9–11 years, at which the estimated mean annual incidence was about 5% in girls and 7% in boys. In 78.4% of the children with injured incisors, one tooth only was injured. The teeth most commonly injured were the upper central incisors, 81.7%; and the most frequent type of injury was an uncomplicated crown fracture, 90.5%.
64 citations
TL;DR: The present summary and the following papers are submitted in partial fulfillment of the requirements for the degree of Doctor Odontologiae at the University of Bergen.
Abstract: The present summary and the following papers (I-VII) are submitted in partial fulfillment of the requirements for the degree of Doctor Odontologiae at the University of Bergen.I: Growth of dental plaque on hydroxyapatite splints. A method of studying early plaque morphology. J. Periodontal Res. 1974, 9, 135-146II: Pellicle formation on hydroxyapatite splints attached to the human dentition: Morphologic confirmation of the concept of adsorption. Arch. Oral Biol. 1975, 20, 739-742III: Scanning and transmission electron microscope study of pellicle morphogenesis. Scand. J. Dent. Res. 1977, 85, 217-231IV: Early dental plaque morphogenesis. A scanning electron microscope study using the hydroxyapatite splint model and a low-sucrose diet. J. Periodontal Res. 1977, 12, 73-89V: Ultrastructural study of early dental plaque formation. J. Periodontal Res. 1978, 13, 391-409VI: Dental plaque morphology as revealed by direct observation and by replicating techniques. Acta Odontol. Scand. 1978, 36, 279-288 Co-author: F....
63 citations
TL;DR: The observation that the intradentinal nerves were confined to the predentin and the most pulpal part of the dentin supports the theory that surface stimulation on dentin has an indirect effect on the nerves activated by movements in the liquid of the Dentinal tubules.
Abstract: The innervation of the predentin and inner part of the mineralized dentin was studied at the ultrastructural level in ten premolars. Each tooth was divided into fifteen different parts, each containing odontoblasts, predentin and dentin. It was found that the innervation in the coronal dentin was more compact than in the root dentin. Within the coronal dentin itself, the most densely innervated area was the dentin covering the pulp horns. No nerves were identified more than 100 microns from the pulp-dentinal border. No nervous structures were found in the mineralized dentin of the root. Nervous structures which seemed to have no connection with the odontoblastic processes were frequently observed in the predentin of the root. Signs of degeneration of the nervous structures of the predentin of the root was also a common finding. The observation that the intradentinal nerves were confined to the predentin and the most pulpal part of the dentin supports the theory that surface stimulation on dentin has an indirect effect on the nerves activated by movements in the liquid of the dentinal tubules.
62 citations
TL;DR: The taste acuity at the midline of the hard and soft palate near their junction and, for comparison, on representative areas of the tongue was determined in 80 subjects aged 11-79 years by applying test solutions of the four basic tastes.
Abstract: The taste acuity at the midline of the hard and soft palate near their junction and, for comparison, on representative areas of the tongue was determined in 80 subjects aged 11-79 years by applying test solutions of the four basic tastes. Twenty-one subjects (26 %) could identify at least one taste on the hard palate but none could recognize all four tastes. Seventy subjects (87 %) could identify at least one taste on the soft palate and 37 subjects (46 %) could recognize all four tastes. Taste thresholds were much higher on the hard palate than on the tongue and were in most cases higher on the soft palate than on the tongue. The ability to recognize all four tastes was less frequent in older than in younger subjects and the difference was greatest on the soft palate and least at the foliate papillae. The differences were greatest for citric acid and least for sucrose. There was a tendency to lower thresholds for women compared to men for all four tastes on all areas examined which was most pronounced on...
55 citations
TL;DR: An investigation was undertaken of 77 denture wearers to study the incidence of yeasts in the angles of the mouth, denturebearing mucosa, dentures base, the throat and the gastrointestinal tract, and the influence of oral local treatment with an antifungal agent (Mycostatin®) on the yeast flora in the same sites was studied.
Abstract: An investigation was undertaken of 77 denture wearers to study the incidence of yeasts in the angles of the mouth, denturebearing mucosa, denture base, the throat and the gastrointestinal tract. Fifty-one denture wearers exhibited denture stomatitis and 26 showed no clinical signs of inflammation of the palatal mucosa (controls). In addition the influence of oral local treatment with an antifungal agent (Mycostatin®) on the yeast flora in the same sites was studied in denture wearers with denture stomatitis. The findings suggest a higher rate of yeast colonization in the mouth (100% compared to 40%) and feces (71% compared to 35%) in denture wearers with denture stomatitis than in denture wearers without stomatitis. Similar species of yeasts, predominantly Candida albicans, C. tropicalis and Torulopsis glabrata were identified among the isolates from the oral sites, throat and feces in denture wearers with stomatitis. In denture wearers without stomatitis the yeast species isolated from the oral sites and...
53 citations
TL;DR: It was concluded that patients with osseointegrated oral implant bridges have a masticatory muscle function equal to or approaching that in patients with natural teeth or with bridges supported on natural teeth with the same extension of the dentition.
Abstract: The activity of the anterior and posterior portions of the temporal muscle, the masseter and the upper lip has been studied with electromyography in 13 women with osseointegrated oral implant bridges and compared with that in 10 subjects with natural teeth. The functions examined were chewing and swallowing of apple, bread and peanuts. There was no difference between implant and control subjects in the number of chewing cycles nor in duration of the act of chewing or in the amplitude of the muscle activity during chewing and swallowing. However, the duration of the activity during chewing was longer in the implant than in the control subjects.The number of years of wearing a maxillary implant bridge was found to be of importance for the number of chewing cycles during an act of chewing and for the muscle activity during chewing. Other factors influencing the muscle activity were age, number of occluding tooth units and the extension of the lower implant bridge.It was concluded that patients with osseointe...
42 citations
TL;DR: Fifty-eight patients seen for consultation concerning mandibular dysfunction symptoms were examined utilizing the Helkimo index of dysfunction and electromyographic silent period recordings from masticatory muscles for correlations between the two parameters.
Abstract: Fifty-eight patients seen for consultation concerning mandibular dysfunction symptoms were examined utilizing the Helkimo index of dysfunction and electromyographic silent period recordings from masticatory muscles. The data collected were analyzed for correlations between the two parameters. Several significant correlations were noted between certain variables of the dysfunction index and the duration of the silent period.The mean duration of the silent period increased with increasing dysfunction index value. However, the clinical significance of this correlation is not established as long as we do not know the validity of neither the dysfunction index nor the EMG silent period duration.
42 citations
TL;DR: The condition of complete dentures was studied in an epidemiologic investigation of a representative sample of 241 persons aged 65–79 in the county of Troms in Northern Norway using an index comprising six professionally assessed indicators.
Abstract: The condition of complete dentures was studied in an epidemiologic investigation of a representative sample of 241 persons aged 65–79 in the county of Troms in Northern Norway using an index comprising six professionally assessed indicators. These indicators were: Defects of the dentures, denture material, stability, retention, occlusion and denture-related mucosal lesions. Three scoring systems denoted system 1, 2 and 3 were applied to determine their influence on the distribution of unsatisfactory dentures. System 1 and 2 which contain weighted indicators, differ mainly in the weighting of retention and occlusion, while system 3 has only unweighted dichotomized indicators. The condition of the dentures was graded: Satisfactory—grade 0 and unsatisfactory—grades I, II, III, depending upon the number of unsatisfactory indicators. The result of the judgment did not reveal any significant difference between the systems, although system 3 differed somewhat. Unsatisfactory upper dentures were usually caused by...
TL;DR: The nature and distribution of corrosion products in teeth restored with metal crowns retained by stainless steel posts were examined by means of energy-dispersive X-ray microanalysis, microradiography, and electron microscopy.
Abstract: The nature and distribution of corrosion products in teeth restored with metal crowns retained by stainless steel posts were examined by means of energy-dispersive X-ray microanalysis, microradiography, and electron microscopy. The corrosion products consisted of calcium, phosphorous, iron, chromium, nickel, zinc, stannum and other elements. A possible root fracturing mechanism is discussed.
TL;DR: The effect of extrinsic asthma on periodontal conditions was studied in a group of 30 asthmatic children and results indicate that gingival inflammation is increased in asthma.
Abstract: The effect of extrinsic asthma on periodontal conditions was studied in a group of 30 asthmatic children. Clinical examination revealed that asthmatic children had more gingivitis than their healthy controls. The asthmatic children who received an inhaled corticosteroid as treatment had more severe gingivitis compared with asthmatic children on disodium cromoglycate treatment. The amount of plaque was not altered.The peroxidase activity was assessed from whole saliva. The results revealed that this defense mechanism was not altered in asthma. An enzyme group which is involved in inflammation, the arginine aminopeptidases, was found to be slightly elevated in the gingival fluid of asthmatic children. The results indicate that gingival inflammation is increased in asthma.
TL;DR: There was a tendency towards lower pH-values induced by the maltitrol and sorbitol rinse after the 3-month period compared with before, and no difference in the relative numbers of facultative anaerobic streptococci before and after the test period was found.
Abstract: Lozenges containing hydrogenated starch hydrolysate (Lycasin), maltitol, sorbitol or xylitol were consumed 4 times daily during 3 months by 4 groups of persons (in all 85 subjects). In the maltitol-, sorbitol- and xylitol-group the plque wet weights were of the same magnitude before and after the test period. In the Lycasin-group, a higher value was found after than before the 3-month period (p less than 0.01). The acid production in suspensions of dental plaque material from Lycasin, maltitol and sorbitol expressed as per cent of that from glucose was approximately the same before and after the test period. From xylitol no acid production could be demonstrated either before or after the 3-month period. There were no statistically significant differences between the plaque pH-changes induced by rinsing with 50% solutions of Lycasin, maltitol, sorbitol or xylitol before and after the test period. However, there was a tendency (p less than 0.05) towards lower pH-values induced by the maltitrol and sorbitol rinse after the 3-month period compared with before. No difference in the relative numbers of facultative anaerobic streptococci. Streptococcus mutans or facultative anaerobic lactobacilli before and after the test period was found.
TL;DR: The occurrence of muscle spindles in the anterior digastric muscle in man was investigated and the fibre calibre spectrum of the corresponding nerve was determined, suggesting that they are not an essential source of sensory information.
Abstract: The occurrence of muscle spindles in the anterior digastric muscle in man was investigated and the fibre calibre spectrum of the corresponding nerve was determined. After removal at autopsy from five individuals of both sexes (aged 23–73), the muscles were stained with Weigert's iron hematoxylin-van Gieson stain and the nerves according to the Alzheimer-Mann-Haggqvist method. Altogether 12 spindles were found in five out of ten muscles. Only muscles from one individual were devoid of spindles. This sparsity or absence was supported by analyses of fibre calibre spectra.The small number of spindles and the fact that they do not occur in all muscles or in all individuals, suggest that they are not an essential source of sensory information.
TL;DR: It is concluded that the resting position of the rabbit's incisor is greatly influenced by arterial blood pressure, via the periodontal vessels.
Abstract: Changes in the axial position of the left upper incisor in response to loading by 5-20 g were measured with ultrasonic technique in anesthetized rabbits. The time-response of the load-induced intrusion described a biphasic curve, with a steep initial part followed by a slower part. Maximum amplitudes after 20 s increased with increasing loads. A rise in arterial blood pressure (aortic balloon inflation) resulted in extrusion, while i.v. injection of noradrenaline or papaverine caused intrusion and extrusion, respectively. The responses to loading and changes in blood pressure were largely unaffected by transection of the root, but the effects of pressure changes were severely diminished by local infiltration of the periodontium with noradrenaline. Participation of periodontal blood vessels in the damping of load-induced intrusion was excluded by the finding of roughly equal intrusion curves at low, normal and high blood pressure and up to 38 h after death. We conclude that the resting position of the rabbit's incisor is greatly influenced by arterial blood pressure, via the periodontal vessels. The intrusion in response to loading by up to 20 g is resisted by periodontal fibers only, the blood vessels or the pulpal and periapical tissues and pressure taking no part.
TL;DR: The electrical taste acuity on the hard and soft palate and the tip of the tongue was determined in 140 subjects aged 13-81 years using an electrogustometer constructed for the study.
Abstract: The electrical taste acuity on the hard and soft palate and the tip of the tongue was determined in 140 subjects aged 13-81 years using an electrogustometer constructed for the study. The possible influence of several variables including age, sex, wearing of a full upper denture, smoking as well as medical and social factors on the threshold values was also studied. Taste perception was demonstrated on the soft palate and on an area of the hard palate close to the junction of the hard and soft palate in most subjects. No perception of the electrical taste was found in eleven subjects (8%) on either the hard or the soft palate and in an additional 33 subjects (24%) on the hard palate alone and 2 subjects (1%) on the soft palate alone. The taste thresholds on the hard palate were very high compared to those on the soft palate and those on the tongue. Older subjects generally had higher thresholds than did younger subjects and the differences were greater for the thresholds on the hard and soft palate than for those on the tongue. No statistically significant differences in threshold values were found between women and men, denture wearers and non-denture wearers or smokers and non-smokers.
TL;DR: It was demonstrated that improved reproduction of details from the plaque could be achieved by repeating the replicating procedure, and the findings indicate that plaque formation starts by adsorption and proliferation of individual bacteria on tooth surfaces, and not by Adsorption of aggregates of cells.
Abstract: Plaque formation on buccal tooth surfaces was studied by replica techniques, consisting of impressions using low viscosity silicone impression materials and positive models produced in epoxy resins. Bacterial accumulation occurred near the cemento-enamel junction in 6-hr specimens, and subsequently expanded in a coronal direction. This development took place partly by extensions of single layers of bacteria, and partly by a pattern where the colonization was mostly restricted to vertical enamel cracks. Plaque accumulations were also frequently located in abrasion grooves and surface pits in the enamel, and prolific plaque areas were consistently surrounded by a monolayer of bacterial cells. Globular and hemispheric structures which occurred, especially on root surfaces immediately after cleaning, were probably artefacts caused by air bubbles or remaining moisture. In separate series of experiments it was demonstrated that improved reproduction of details from the plaque could be achieved by repeating the ...
TL;DR: Mycoses of the mouth and nearby areas can be caused by both yeasts and filamentous fungi andYeasts that are part of the normal microbial flora of man, among them especially Candida species, are the most frequent causative agents.
Abstract: Mycoses of the mouth and nearby areas can be caused by both yeasts and filamentous fungi. They may appear either independently or as part of a systemic infection. It is typical of many mycoses that they occur as a consequence of local factors operating in the mouth, or in patients debilitated by severe diseases. Yeasts that are part of the normal microbial flora of man, among them especially Candida species, are the most frequent causative agents. Some tropical or semitropical infections may occur in Scandinavia and Finland, but they are rare. Local therapy with antimycotics is often effective in acute infections, whereas some chronic ones may make systemic administration necessary. Some of these infections are treated surgically.
TL;DR: Clinical and radiographic examination during the postoperative period revealed rapid healing and anchorage of the implant in five of the animals, andLabeling of the mineralizing tissue was attempted using intravenously administered tetracycline and calcein at varying intervals prior to sacrifice, but the labeling results were not impressive.
Abstract: Porous Al2O3 ceramic material with pore size of 100-750 micrometers was used for implants placed subperiosteally as alveolar ridge augmentation onlays in six Cercopithecus monkeys. Clinical and radiographic examination during the postoperative period revealed rapid healing and anchorage of the implant in five of the animals. One implant was lost. The implants were retrieved after 4, 10, 11 and 12 months' implantation time. Histologic and microradiographic examination demonstrated fibrous and bone tissue invasion into the pore system at the base of the subperiosteal implant, with good anchorage of the ceramic material to the jaw. Only fibrous tissue was found to project into the ceramic openings on the implant sides facing the periosteum. Labeling of the mineralizing tissue was attempted using intravenously administered tetracycline (Reverin) and calcein (Calcein) at varying intervals prior to sacrifice, but the labeling results were not impressive.
TL;DR: In general, women, young people and people with a high socioeconomic status had less caries, better oral hygiene and periodontal condition and had received more restorative dental care than the remaining part of the population.
Abstract: Information concerning oral health status was obtained through a clinical and radiographic examination of 297 persons aged 20–69 years out of a population of 358 persons living in a coastal community in Northern Norway. The oral health was generally poor. 71% had one ore more remaining teeth and the dentulous persons had a mean number of 18 remaining teeth. The mean number of DMF teeth was 27,3, while the mean number of decayed teeth was 4,9 and filled teeth 12,0 giving a percent of decayed and filled teeth of 27 and 65 respectively. Only every fourth dentulous person had one or more crowns and/or bridge units and 4% of all teeth had been treated endodontically. 41% of the teeth had visible plaque and 56% of the teeth had one ore more gingival margins bleeding after gentle probing. One fourth of all teeth had gingival pockets exceeding 3 mm and 17% of all teeth showed a bone loss of 20% or more. The number of remaining teeth decreased with increasing age and decreasing income and/or social class. In gener...
TL;DR: Only one fifth of the vascular resistance governing pulpal blood flow is situated within the pulp itself, which means that blood flow in the dental pulp in cats may be influenced by mechanisms located extrapulpally.
Abstract: Pressure in selected microvessels was measured directly on the exposed coronal or apical pulp in one of the upper canine teeth or on the gingiva in a total of 36 cats. The vessels were punctured with glass micropipettes, diameter 1-4 micrometer, and the pressure measured with a modified Wiederhielm servocontrolled counter-pressure technique. Pressures in corresponding vessels in coronal and apical pulp were similar. The pressure in pulpal arterioles, diameter 10-70 micrometer averaged 43 mm Hg, or 36% of mean systemic arterial pressure (PA), while pressure in the pulpal venules, diameter 10-80 micrometer, was on an average 19 mm Hg or 16% of PA. Capillary pressure measured in the coronal pulp averaged 35 mm Hg. Mean arterial systemic pressure was 124 mm Hg. The total vascular pressure drop within the pulp was only 20% of the total systemic arteriovenous pressure difference. Accordingly, only one fifth of the vascular resistance governing pulpal blood flow is situated within the pulp itself. This means that blood flow in the dental pulp in cats may be influenced by mechanisms located extrapulpally. In gingiva only venular pressure was measured, which averaged 19 mm Hg.
TL;DR: The treatment profile according to age showed that younger people used most of their treatment time on consultations, preventive measures and conservative treatments, while fixed and removable prosthetics constituted a major part of the treatment time among elderly people.
Abstract: The utilization of dental services was studied by means of records from dentist's files, a method which permits gathering of detailed information with high reliability and validity. 53% of the adult population of 358 persons living in a coastal community in Northern Norway had visited a dentist during a period of two years. In the group of 13% who were considered to be regular treatment attenders, number of teeth, sex and socio-economical status were the most influential predictors of utilization. Among the 182 persons with 10 or more remaining teeth, 59% had made preventive and restorative dental visits, and in this group there was a dominating proportion of women, young people and people with high income and/or social class. In contrast, only six persons out of 61 with one to nine remaining teeth had made such visits. People in social class 3 were overrepresented among the 26% of the population who visited a dentist because of extractions or complete denture services. The treatment profile according to ...
TL;DR: All the present drug combinations known to enhance central dopaminergic function seemed to increase irritability and disposition to experimental oral dyskinesias, especially when a sensory stimulus was applied at the same time or the drug had an amine-releasing effect (pheniprazine).
Abstract: Aggression has been suggested as one of the etiologic factors in bruxism. Experimental bruxism, audible, nonfunctional grinding or clenching of the teeth, was provoked in aggressive animals by drugs affecting central dopaminergic systems. Electric foot-stimulation was used to induce aggression, evident as the threatening or fighting position, in paired male Wistar rats. After initial stimulation, shocks were given only to maintain the characteristic fighting pose. Apomorphine facilitated induction of aggressive behaviour by electric shocks, and the rats receiving both treatments showed bruxism more frequently than controls subjected to shocks alone: up to 95 bruxism periods registered by a tape recorder during 30 min, as opposed to a few sporadic periods in the controls. Without shocks, apomorphine-treated rats displayed stereotypy with locomotion and biting of various objects. Aggression and bruxism were not equally successfully induced after L-dopa given with a peripheral inhibitor of aromatic amino aci...
TL;DR: Normal and fluorotic primary and permanent teeth were demineralized in 10% EDTA at pH 7 for varying periods of time up to 4 weeks to remove almost complete removal of the outer enamel.
Abstract: Normal and fluorotic primary and permanent teeth were demineralized in 10% EDTA at pH 7 for varying periods of time up to 4 weeks. The fluorotic teeth initially dissolved at a much slower rate than non-fluorotic specimens and appeared to contain more organic material.After almost complete removal of the outer enamel a soft organic layer remained on the dentin surface. This consisted of a fine flbrillar mesh and some more dense material. After four weeks much of the organic material had disappeared leaving only a thin membrane on the dentin surface.
TL;DR: Tooth root replica implants made from alumina ceramic material of solid structure coated with a porous layer, were used as dental implants in monkeys, finding fibrous and mineralized tissue ingrowth of the porous layer of the implants was found.
Abstract: Tooth root replica implants made from alumina ceramic material of solid structure coated with a porous layer, were used as dental implants in monkeys. The porous coating was 1/2 mm thick and had pore sizes within 50–200 μm range, with a 30 % degree of porosity. Ten implants were inserted into prepared sockets in the mandible of 5 Cercopithecus monkeys. After submerged implantation periods varying from 5 to 15 weeks, a perforating steel post was introduced through the covering gingiva into the artificial root canal of the implants. The animals were sacrificed after 6 weeks, 2, 3 and 4 months. Three out of the total number of 10 implants were lost. The remaining 7 specimens were retrieved for histologic and microradiographic examination. Fibrous and mineralized tissue ingrowth of the porous layer of the implants was found. No adverse reactions of the adjacent bone were demonstrable. The implants became firmly anchored to the host and no epithelial downgrowth along the ceramic was found.
TL;DR: The present investigation confirmed the staining ability of an antibacterial quarternary ammonium salt, benzethoniumchloride, used as a 2% additive to a dentifrice, and a weak chelator did not alter the discoloration tendency.
Abstract: Extrinsic brown tooth discolorations are frequently detected in connection with antibacterial agents used for chemical plaque control. The present investigation confirmed the staining ability of an antibacterial quarternary ammonium salt, benzethoniumchloride, used as a 2% additive to a dentifrice. A weak chelator did not alter the discoloration tendency. Extrinsic discoloration was evaluated both by direct inspection, from color photographs and by using a microphotometric technique. The discoloration tendency was well demonstrated by all three techniques. Evaluation from the color photographs, however, may be preferable in epidemiological surveys while the microphotometric technique may possess certain advantages in detailed experimental discoloration studies.
TL;DR: It has been found that oxide-forming elements in the alloy are important for the blood strength between the metal and the procelain.
Abstract: It has been found that oxide-forming elements in the alloy are important for the bond strength between the metal and the porcelain. The purpose of the present investigation was to study the formation of oxides during pretreatment and firing of porcelain. Four commercially available Cera-mo-Metal alloys were studied. The specimens were heated at 980 °C for five hours in air, and the weight was continuously recorded. In addition porcelain was fired on to the alloys. Metallographic examinations were conducted on both oxidized and fired specimens.The weight gain data also indicated an increased oxygen uptake with a larger amount of oxidizable elements in the alloy. Most of the oxygen gain and time indicated that the oxygen uptake was diffusion controlled. The weight gain data also indicated an increased oxygen uptake with larger amount of oxidizable elements in the alloy. Most of the oxygen in the oxidized alloys was located as oxide along grain boundaries in the metal.
TL;DR: It is concluded that the radiographic signs in the temporomandibular joint of reduced joint space, subcortical sclerosis of the condyle and flattening of the lateral part of the Condyle are interrelated and probably characteristic of osteoarthrosis, and that these relationships are similar to those that occur in the hand joints.
Abstract: The temporomandibular joints of 64 patients and the hand joints of 62 patients with mandibular pain and/or dysfunction were exposed in oblique lateral transcranial, transmaxillary, and dorso-volar projections. The relationship between radiographic signs generally ascribed to osteoarthrosis was investigated. Indices were constructed to quantify the radiographic findings in the two joints. In the temporomandibular joint statistically significant age-independent correlations were found between flattening of the lateral part of the condyle, subcortical sclerosis of the condyle and reduced joint space. In the hand joints statistically significant age-independent correlations were found between osteophytes, subcortical sclerosis, eroded/absent cortical outlining, reduced/obliterated joint space and dislocations. No statistically significant correlation could be found between radiographic findings in the temporomandibular and hand joints. It is concluded that the radiographic signs in the temporomandibular joint of reduced joint space, subcortical sclerosis of the condyle and flattening of the lateral part of the condyle are interrelated and probably characteristic of osteoarthrosis, and that these relationships are similar to those that occur in the hand joints.
TL;DR: The possibility of dityrosine cross-linking in vivo in human oral fluid seems to be limited compared with e.g. human milk or macaque saliva where the concentration of SCN ions is low but the activity of lactoperoxidase is considerably high.
Abstract: The study dealt with the formation of dityrosine - a cross-link in some proteins including collagen - by human salivary lactoperoxidase. Dityrosine formation was found at pH range 6.6 to 9.3 with maximum reaction velocity at pH 8.5. However, thiocyanate ions at physiological salivary concentrations inhibited dityrosine formation by 70 to 80 per cent compared with the optimum rate. The inhibition seemed to result from the competition of SCN ions and L-tyrosine for the same binding site on enzyme surface. The possibility of dityrosine cross-linking in vivo in human oral fluid seems to be limited compared with e.g. human milk or macaque saliva where the concentration of SCN ions is low but the activity of lactoperoxidase is considerably high.