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PubMed2005

Effect of topical fluoride and fluoride varnish on in vitro root surface lesions.

PURPOSE: To evaluate the effect of a fluoride varnish on demineralization and remineralization of root surfaces in vitro. METHODS: 80 caries-free teeth were selected from a large pool of extracted anterior and premolar teeth from elderly patients. Acid resistant nail varnish was painted on all surfaces except for a window (l x 4 mm) on the buccal or lingual root surfaces. Teeth were randomly divided into four treatment groups: CONTROL: washed with deionized/distilled water; Daily gel: treated with Karigel-N (5,000 ppm) for 4 minutes daily; Weekly gel: treated with Karigel-N for 4 minutes weekly; and Weekly varnish: treated with Duraflor (22,600 ppm) weekly (the varnish was removed 24 hours after each application). Teeth were then placed in a cycle of demineralization (6 hours at pH 4.3) and remineralization (17 hours at pH 7.0) for 21 days. Half the specimens of each group were brushed with no dentifrice for 10 seconds twice daily. Specimens were evaluated under polarized light microscopy and contact microradiography. The depth of each lesion and width of the remineralization bands were measured. An ANOVA model was used to assess the effect of different treatments. RESULTS: The control group had the deepest lesions and the daily gel group had the shallowest lesions. The weekly varnish group was found to have significantly shallower lesions than the weekly gel group. The varnish brushing subgroup had significantly deeper lesions than varnish non-brushing subgroup (P = 0.01). Remineralization bands were detectable in most lesions. There was no significant difference in band width between different groups (F = 0.634, P = 0.594). However, a significant difference was found when remineralization bands were calculated as percentage of lesion depth between different groups (F = 4.24, P = 0.001). The varnish non-brushing subgroup had significantly higher percentage than the control group, but daily gel non-brushing had the highest percentage. Brushing was a significant factor in the varnish group. Lesions were significantly shallower in the non-brushing varnish subgroup.

Aged↗
PubMed2005

Asthma inhalers and subsurface enamel demineralisation: an in situ pilot study.

AIM: The purpose of this pilot study was to identify the subsurface enamel demineralising potential of two possible acidogenic lactose-based powders and their corresponding generic pump inhalers. METHODS: Ten healthy non-asthmatic adults participated in a 5- leg randomised crossover study including a 10% sucrose control. A twice-daily 400 microg dose of inhaler was applied in vitro to a demineralised enamel slab on the buccal flange of a mandibular removable appliance before in situ placement for 14 days each. Lesion parameters were determined using transverse microradiography and digitised image analysis. RESULTS: Minimal demineralisation occurred with sucrose, both pump and one powder inhaler. The remaining powder was associated with remineralisation (p = 0.29). Overall, mean lesion depth increased (p = 0.12). CONCLUSION: Asthma inhalers failed to demonstrate a significant acidogenic/cariogenic effect.

Administration, Inhalation↗
PubMed1991

[A new application of plastination in bone histology].

The plastination techniques originally developed for macroscopy can be modified for the preparation of plastinated sections for microscopy. Particularly good penetration of the specimen during preparation of the histological section is obtained, when the techniques described for freeze substitution, degreasing and forced impregnation with resin are employed. The different types of polymers are compared to determine the particular advantages and disadvantages of each. The sectioning technique and the use of histological stains are described for both undecalcified and decalcified bones. The modified Spalteholz technique with decalcification of sections and second plastination procedure for the preparation of transparent decalcified bone sections is described. This makes it possible to produce plane parallel standardized sections for morphometric examination of the vascular structure of the bone. The possible uses of the plastination for the histological examination procedures currently in use, such as fluorescence microscopy, microangiography and microradiography, are shown. The relative values of different microangiographic techniques have been determined for the first time by means of further developments of the Spalteholz and plastination techniques, because they have provided the possibility of standardizing sections. Thus, the plastination technique appears to be especially useful for the examination of microscopic specimens.

Animals↗
PubMed1990

[Experimental studies of direct pulp capping in permanent teeth with incompletely formed apices].

In permanent teeth described as having incompleted roots, dentin is still in the process of deposition on internal dentin walls and the root is in the process of completion. The purpose of this study of dog's immature permanent teeth was to investigate pulp healing and continuous root and internal dentin-wall developments after direct pulp capping with two types of calcium hydroxide paste on mechanically exposed pulp. Material and methods In this study, 148 vital permanent premolars with incompletely formed apices were obtained from 26 dogs (6 months old). The animals were generally anesthetized with 5% sodium pentobarbital, and a cavity was prepared on the occlusal surface of each experimental tooth using an air turban handpiece with diamond bur. After the cavity preparation, the central pulp horn of each tooth was mechanically exposed with a sterile round bur (ISO No. 007, 2/0). In experimental teeth on the right side, a calcium hydroxide-iodoform paste "Calvital" was applied on the exposed pulp, in experimental teeth on the left side, the exposed pulp was capped with a hard-setting calcium hydroxide paste "Dycal". The cavities were lined with first a zinc-oxide eugenol cement and then a zinc-phosphate cement. Then the cavities were filled with silver amalgam. The dogs were sacrificed by means of sodium pentobarbital at intervals of 3, 7, 14, 28, and 56 days after direct pulp capping. Their jaws and teeth were removed, fixed with formalin, and 100 cases out of 148 teeth with bones from 20 dogs were decalcified, and embedded in celloidin. Each specimen was serially sectioned, stained with hematoxylin-eosin, thionin-picric acid and van Gieson's stain, and evaluated microscopically. In order to identify postoperative dentin formation, intravenous injections of tetracycline were administered to the remaining 6 dogs (48 teeth) at various intervals after the experimental procedure. Two dogs were sacrificed each of the experimental periods. Specimens were embedded in resin and sectioned to a thickness of 50 microns. Undecalcified ground sections were observed by contact microradiography, and tetracycline labeling was evaluated by ultraviolet light. Results and Conclusion 1. Pathological evaluations of the 2 groups "Calvital" group: 49 (98.0%) of 50 cases were evaluated as good, and 1 case (2.0%) as moderately good. "Dycal" group: 31 (62.0%) of 50 cases were evaluated as good, 15 (30.0%) as moderately good, and 4 (8.0%) as bad.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

[Pathological studies on the lumbar facet joints].

Relationship between changes of the bony architecture and remodeling in the facet joints of the lumbar spine was studied in cadaveric specimens, using the method of microradiography. The facetal angle was 59 degrees at L1-2, 65 degrees at L2-3, 75 degrees at L3-4 and 92 degrees at L4-5. The subchondral compact bone volume was higher at the anterior part in all cases. The greater compact bone volume was found in the more sagittally facing facets, asymmetrical facets and facets with disc degeneration. Highly mineralized tissues in the trabeculae were observed in the degenerative facets. These tissues consisted of old calcified fibrocartilage, left alone as the result of continued remodeling. The degenerative changes in the lumbar facet joints probably start as calcification of the part where the ligamentum flavum attaches, followed by new bone formation and transformation of the joints.

Adult↗
PubMed1991

Interactions between fluoride and plaque in the remineralization of enamel caries-like lesions.

The effect of fluoride and plaque, separately and together on the remineralization of early artificial caries lesions was studied in a group of volunteers in a double-blind randomized study design. Artificial caries lesions produced in slabs of human enamel were mounted buccally in silver bands cemented bilaterally to the mandibular first molar teeth. Volunteers wore the bands for two 2-week periods, rinsing daily with either a placebo or a 500 ppm fluoride mouthrinse. Plaque accumulation was encouraged by placing Dacron gauze over one of each pair of slabs. Sections were cut from the lesions and analyzed by microradiography followed by microdensitometry and image analysis. Microdensitometric data revealed that non-significant increases in mineralization had occurred in all of the test groups. However, the image analysis results indicated that significant remineralization had occurred in lesions after 2 weeks on the fluoride rinse regimen, with no significant remineralization in lesions exposed to the placebo. The presence or absence of plaque over the lesions had no effect on the amount of remineralization induced on the fluoride rinse regimen.

Analysis of Variance↗
PubMed1991

The effect of 2-O-stearoyl-glycerol 1,3-bisphosphate on the demineralization of dental enamel in vitro.

Parts of the buccal and lingual enamel surfaces of sound human third molars were treated with a test compound, and the non-treated parts served as control. After the treatment both parts were demineralized, and the artificial caries lesions were analyzed by means of quantitative microradiography. Treatment during only 1 minute with an aqueous solution of 1.5 mmol/l of the surface active compound 2-O-stearoyl-glycerol 1,3-bisphosphate (Glydip) resulted in a decrease in the rate of enamel demineralization by about 60%. When Glydip was dissolved in a toothpaste/water slurry it inhibited the demineralization by about 30%. When the enamel was covered by a salivary pellicle prior to the application of the slurry, the inhibition of the demineralization disappeared. However, when Glydip was applied in an aqueous solution, the presence of a salivary pellicle did not interfere with the decreasing effect of Glydip on the demineralization. It is concluded that Glydip has promising properties for its use as an anti-caries agent, in combination with fluoride.

Dental Caries↗
PubMed1991

[Histological investigation on hydroxyapatite ceramics as materials of artificial bone grafts in the cervical spine].

UNLABELLED: The purpose of this study is to understand the utility of the hydroxyapatite (HA) ceramics as artificial bone graft substances in the cervical spine. METHOD: Dense and porous HA were implanted into the vertebral body and intervertebral space of the adult dog cervical spine and the implanted cervical bones were removed 4, 8 and 24 weeks after implantation and examined by contact microradiography (CMR), and histological observations of the non-decalcified material stained with Van Gieson's and decalcified material stained with hematoxylin and eosin. RESULTS AND CONCLUSION: 1. Sufficient formation of new bone with the bone marrow was recognized on the surface and in the pores of the porous HA being implanted to the cervical vertebra. 2. Dense HA was inadequate for the implantation into cervical areas because of its physical nature, such as glass-like smooth surface and the extreme hardness. 3. HA was not fit for usage in the intervertebral space of the cervical spine because of its total ineffectiveness in the functions such as the supporting heavy weight of the head and the mobility and its histologically poor activity of the new bone formation in the intervertebral space.

Animals↗
PubMedDate not supplied

Contribution to the study of tetracycline bone side-effects. Absence of calcium deposition impairment in the trabecular bone of a patient treated during 3.5 years with doxycycline.

Tetracyclines are easily incorporated into bone; whether bone formation is impaired during this process is still a matter of debate. We therefore studied, by histomorphometry, fluorescence microscopy, and microradiography, a sample of trabecular bone from a patient with a total hip arthroplasty, treated without interruption for 3.5 years with doxycycline because of a pertrochanteric abscess. Absence of osteomalacia and a low-mineralization score of the edges of the trabeculae similar to that observed in a control group of 12 subjects suggest no interference by doxycycline with calcium deposition in bone.

Arthritis, Infectious↗
PubMed1990

[A histopathological study on hypoplasia of the enamel].

The research on the development and injury of the hard tissue of teeth was studied by the pedodontic departments of nine dental schools. We participated in this research and studied histopathologically hypoplasia of the enamel in particular. There were seven selected teeth which had obvious hypoplasia of the enamel. We conducted observations with the naked eye, replica, general microscopy, polarized light microscopy, fluorescence microscopy, and microradiography. Moreover we studied to classify these cases into three types, that is to say, the injury factors of whole body, locality, and unknown origin. The results obtained were as follows. 1) As for the injury factors for the whole body, the bottom of the enamel defects were located corresponding to the incremental line of Retzius in the case of enamel hypoplasia of the deciduous teeth. Also enamel hypoplasia was located near the dentino-enamel junction corresponding to the surface of hypoplasia. 2) As for the injury factors with respect to locality, the bottom of enamel defects were located corresponding to the incremental line of Retzius. The dentino-enamel junction was irregular and discontinuous, still more a part of that area, and the dentin protruded or was exposed. 3) As for the injury factors of unknown origin, hypoplasia was located from the surface of the enamel but it did not spread. Also the hypoplasia of the enamel did not correspond to the incremental line of Retzius. 4) Five cases had fluorescence lines in enamel or dentin.

Dental Enamel Hypoplasia↗
PubMed1991

Bilateral tibial components of different cementless designs and materials. Microradiographic, backscattered imaging, and histologic analysis.

Postmortem evaluation was conducted on two cementless knee prostheses considered clinically successful. The two retrieved uncemented porous-coated tibial components of different designs, and materials were evaluated by microradiography, backscattered electron (BSE) imaging, and light microscopy. The right prosthesis, in place for 25 months, was a Porous-Coated Anatomic (PCA) implant with double-layered, sintered, cobalt-chromium alloy beads. The left prosthesis was a Natural-Knee (N-K) implant with a porous coating of cancellous-structured pure titanium implanted for 19 months. A quantitative microradiographic index, the appositional bone index (ABI), was developed to indicate the probability of bone ingrowth occurring into the porous coating. The ABI is a ratio of bone in apposition with porous coating divided by the total amount of porous coating available. The PCA had an average ABI of 9%, and the N-K, 67%. BSE images of the PCA demonstrated no bone within the porous coating. BSE images of the N-K implant showed bone ingrowth into 22% of the pore volume when porous coating was in apposition to host bone. Histology of the PCA revealed fibrous connective tissue throughout the porous coating and between the porous coating-bone interface. Histology of the N-K implant revealed bone ingrowth and osteoblastic activity along the bone within the porous coating.

Aged↗
PubMed1990

Effect of fluoride release from a fluoride-containing composite resin on secondary caries: an in vitro study.

The effect of fluoride, released from a fluoride-containing composite resin, on secondary caries was investigated by quantitative microradiography. In all teeth investigated, less demineralization was found near the composite resin than was found at a distance of a few millimeters from the material after an acid attack. The presence of the fluoride-releasing composite resin reduced the lesion depth measured after an acid attack by about 35%. Therefore, in vivo, a reduction of recurrent caries may be expected around fluoride-containing composite resins.

Adult↗
PubMed1990

Studies on the distribution of mineral elements in the tooth of zinc-deficient rats.

Elemental analysis of plaque-like black deposits noted on the surface of teeth in zinc-deficient rats at necropsy was performed. Rats deficient in zinc show signs of abnormality in iron metabolism and increase or accumulation of iron in plasma and tissues. This study was designed, therefore, to examine the plasma and salivary levels of iron and other elements and to determine the distribution of mineral elements in the dental substances of zinc-deficient rats by contact microradiography, electron probe microanalysis (EPMA) and X-ray fluorescent element mapping spectrometry (XEMS) on ground sections of teeth. Rat tooth specimens were analyzed also for zinc, iron, copper and manganese using colorimetry and Inductively Coupled Plasma, ICP. EPMA and XEMS analyses revealed the presence of iron on the enamel surface of maxillary molars teeth of zinc-deficient rats. However, no such deposition was seen on those of controls. The zinc-deficient rats showed higher iron concentration in mixed saliva and in plasma, compared with the controls. Thus, the sign of abnormality in iron metabolism noted in the oral cavity of zinc-deficient rats was investigated by EPMA and XEMS analyses, with discussion on the origin of supradental iron deposits.

Animals↗
PubMed1990

[Microradiographic investigations of carious changes in the enamel in the ground sections made perpendicularly to tooth axis].

Carious changes in the enamel in the undermineralized ground sections made perpendicularly to tooth axis were investigated using microradiography. By this way, relationship between carious invasion and the enamel lamellae and tuft, which has been not able to be examined in the longitudinal ground sections, could be clarified. 1) Direction of progress of demineralization and contour of demineralization front in the enamel are closely related to arrangement of enamel prisms. This findings strongly suggest that carious demineralization progresses along the enamel prisms. 2) Mode of carious demineralization in the enamel lamellae can be divided into two types; in the first type, demineralization progresses through the enamel lamellae more quickly than in the surrounding enamel and, in the second type, the enamel lamellae and its surrounding enamel show higher mineralization degree than the demineralized part in the rest of enamel, probably due to remineralization. The second type is observed more frequently than the first. 3) Mode of carious demineralization in the enamel tuft are also divided into two types; the first type which shows that demineralization progresses more quickly through the enamel tuft than the surrounding enamel and the second type that the enamel tuft and its surrounding narrow enamel are highly mineralized probably due to remineralization, whereas the rest of enamel is prominently demineralized. The second type is more frequently observed than the first. 4) In the ground sections made perpendicularly to tooth axis, it is more clearly observed that the interprismatic area is very highly remineralized whereas the main body of prism is easily demineralized, than in the longitudinal ground sections. 5) Striae of Retzius is composed of the band which appear to resist to demineralization and that which is easily demineralized. However, in the later case, demineralization which progresses laterally along the band can not be observed. 6) The degree and width of hypermineralized layer appeared in sound enamel along the demineralization front seem to be related to the rate of demineralization and arrangement of enamel prisms.

Dental Caries↗
PubMed1990

Quantitative determination of alveolar bone density using digital image analysis of microradiographs.

Horizontal 100 microns ground sections of 20 alveolar bone specimens from adult human mandibles obtained from autopsies were prepared for microradiography. Quantitative analysis of bone density of the alveolar cortex was performed using a semiautomatic digital image analysis system (KONTRON). The results demonstrated that bone density was higher in the lingual than in the labial alveolar cortex (p less than 0.05). In addition, the coronal portion of alveolar cortical bone was significantly more porous than the medical and apical ones (p less than 0.05). These variances were primarily due to increased canal size rather than to an increased number of canals. No significant age dependent changes in bone density could be determined.

Adolescent↗
PubMed1990

The vascular repair of an experimental osteotomy held in an external fixator.

The vascular repair of a lower tibial transverse osteotomy in the New Zealand white rabbit held in an external fixator was studied in three groups. In the first group, composed of 18 animals, the osteotomy gap was maintained throughout repair. Three animals were killed every two weeks up to 12 weeks postoperatively. In the second group, composed of three animals killed at six weeks, the fragments were brought into contact. In a third and similar group, the osteotomy was compressed. Plain roentgenograms were taken weekly, and intraarterial perfusion with Micropaque was performed when the animals were killed. Roentgenography using fine-grain film, microradiography, and histology were carried out on a midsagittal tibial slice. The results showed that following transverse osteotomy in which the gap was maintained, vascular union of the proximal and distal cortices and associated external callus masses had usually occurred by ten weeks postoperatively. However, an occasional hypovascular zone at the osteotomy site at 12 weeks was associated with fibrous delayed union. In contrast, when apposition or compression of the fragments was used, repair was accelerated, and cortical bone union was established at six weeks. Vascular union of the fragments occurred predominantly through the medullary vessels. The results emphasize the overriding clinical importance of abolition of a fracture gap to achieve rapid revascularization of a fracture and its union by bone.

Angiography↗
PubMed1989

[Experimental study on tooth fractures in young rats].

The influence of tooth fractures on growth of rat incisors was examined with soft X-ray radiography, xeroradiography and microradiography. Thirty young rats were used in this study and experimental fractures were produced on the mandibular left incisors. Radiological observations were carried out immediately, 7, 14, 21, 28 and 35 days after fracturing. The soft X-ray radiograms obtained immediately after fracturing showed clear radiolucent images. The radiopacity of the fractured regions gradually increased from the 7th day. Enamel hypoplasia was observed from the 7th day, and it moved towards the edge of the incisors with the growth of the fractured teeth. The xeroradiograms obtained at each term demonstrated as same findings as those obtained with soft X-ray radiography. The microradiograms obtained immediately after fracturing showed no noteworthy findings except for the clear radiolucent area of the fractured regions. Fine radiopaque lines along the edges of fractured regions were observed from the 7th day. Dentin-like radiopaque calcified masses were observed from the 14th day.

Animals↗
PubMed1989

Regional odontodysplasia: new histopathological data.

Light microscopy, microradiography, SEM and TEM of 4 tooth follicles in a 12-year-old caucasian girl presenting regional odontodysplasia showed widespread globular dentin, calcifications located in the enlarged pulp chambers, hypoplastic and hypomineralized enamel. Hypomineralized strands were sandwiched between two normal enamel layers, which indicates that amelogenesis, interrupted for a while, has once more become established. The enamel surface was covered with calcoglobules. Numerous rounded calcifications were scattered within the dental follicles. Some of these occurred in microfibrils (possibly oxytalan fibers), distinct from collagen fibers. Calcification of the sheath surrounding epithelial rests was a conspicuous feature. The fibroblasts in contact with calcifications developed numerous cytoplasmic extensions, which suggests that they may have assumed a phagocytosis behaviour.

Child↗