Root resorption and pulpal changes due to intrusive force

Intrusion has been regarded as a controversial topic in the literature. It is apparent from many studies that excessive forces applied in orthodontic treatment might lead to undesirable results such as circulatory disturbances, pulp degeneration, calcification and even necrosis. This study was performed to observe the reaction of pulp and roots following tooth intrusion. Material consisted of four first premolar teeth of two adult patients. One premolar of each patient was intruded orthodontically and the other premolars were taken as controls. The palatal roots of the experimental teeth were cut and examined in scanning electron microscope (SEM) and the pulps of the teeth were examined in transmission electron microscope (TEM). At SEM examination, root surfaces of intruded teeth showed resorption cavities of different diameters and depths. At TEM examination, vascular degeneration was the main change in the pulps of experimental teeth.     

Periapical replacement resorption of permanent, vital, endodontically treated incisors after orthodontic movement: report of two cases

Radiographic observations show that periapical replacement resorption (PARR) is a frequent and unpredictable sequella of orthodontic movement of permanent maxillary incisors. Only the apical root portion undergoes resorption, and it is subsequently replaced with normal bone. PARR also occurs without orthodontic tooth movement, but these resorptions differ as to type and location. PARR clearly occurs in teeth with vital pulps after orthodontic movement; however, our two cases and a review of 43 other cases indicate that endodontically treated incisors show a statistically significant lesser frequency and severity of apical resorption than untreated teeth. The role the vital pulp plays in this apical resorption is yet to be determined. A hypothetical explanation is offered suggesting that pulpal neuropeptides may be involved in PARR in both vital and endodontically treated incisors. The role calcium hydroxide plays in endodontically treated teeth is also considered.     

Rapid and long-lasting suppression of the ATF-2 transcription factor is a common response to neuronal injury

To determine if intestinal stromal cells secrete diffusible factors such as insulin-like growth factors (IGFs) capable of regulating epithelial cell growth in vitro, stromal cells were isolated by enzymatic digestion of rat intestine. Incorporation of [3H]thymidine into DNA and [14C]leucine into protein of IEC-6 cells, a model intestinal epithelial cell line, was significantly increased (two- to threefold) when the IEC-6 cells were co-cultured with stromal cells, relative to IEC-6 cells grown alone. Medium conditioned by stromal cells stimulated DNA synthesis of IEC-6 cells in a dose-dependent manner. Analysis of the conditioned medium revealed that intestinal stromal cells secreted IGF-I, but little IGF-II, in addition to an M(r) 32,000 IGF-binding protein (IGFBP-2) and an IGFBP having M(r) approximately 24,000. We conclude that rat intestinal stromal cells secrete one or more diffusible factors, which may include IGF-I and IGFBPs, capable of stimulating proliferation of IEC-6 cells in vitro.     

Comparative study of antifungal activity of sertaconazole, terbinafine, and bifonazole against clinical isolates of Candida spp., Cryptococcus neoformans and dermatophytes

The aim of this study was to investigate the visibility of secondary caries in the gingivobuccal and gingivolingual corners of teeth restored with amalgam restorations. Standard Class II cavities were created in 15 orthodontically extracted mandibular premolar teeth, and the teeth were randomly divided into five groups of three teeth each. In four of the groups, a 1.0- or 1.5-mm cavity was prepared in the gingivolingual or gingivobuccal corner of the restoration. No lesions were created in group 5, the control group. The teeth were restored with amalgam. The teeth were adapted in the actual tooth space of 15 volunteers with one mandibular premolar missing. Radiographs of each patient were taken with the bisecting-angle technique and the bite wing technique. The radiographs were sorted at random and given to 15 members of the professoriate who were often involved in detecting caries and to 17 members who were not normally involved in detecting caries. The bitewing technique was found to be more reliable than the bisecting-angle technique in detecting secondary caries in gingivobuccal approximal corners (P < .05). It was also found that, in group 1, the bisecting-angle technique was more reliable than the bitewing technique in detecting caries in gingivolingual corners (P < .05). No significant differences were found in the correct evaluation of radiographs between the faculty who were normally involved in the detection of caries and those who were not.     

Biocompatibility of Optibond and XR-Bond adhesive systems in nonhuman primate teeth

This study evaluated the histologic responses of two different adhesive systems on the teeth of seven healthy adult monkeys. Class V cavities in 128 teeth were observed at 7,21 to 27, and 90 to 97 days. Statistical data showed no significant differences in pulp inflammation between the Optibond (Kerr), XR-Bond (Kerr), and IRM (Caulk) groups in pulps at the three time intervals. Some odontoblastic disruption and inflammation was seen in pulps restored with XR-Primer at the three time intervals. Pulp healing was similar in teeth treated with both direct-capped Optibond and calcium hydroxide, and there was no significant increase in pulpal inflammation with time. No abscesses or necrotic pulps were seen in any teeth. Optibond and XR-Bond adhesive systems are biologically acceptable in nonhuman primate pulp tissues.     

The effects of thrombocytopenia on the activated coagulation time

Cortical efferents grow from deep cortical layers to innervate numerous subcortical structures late in embryogenesis. The mechanisms that control their development are poorly understood. We co-cultured organotypic embryonic cortical explants with other tissues, maintaining a distance between them to avoid contact-mediated interactions. At embryonic day 15, when the cortical plate comprises only cells of the deep cortical layers, outgrowth from cultured cortex was stimulated by co-cultured subcortical structures, but not by additional cortex or liver. These data support the hypothesis that diffusible factors from subcortical structures, and not from the cortex itself, enhance cortical efferent growth.     

The effect of different reinforced glass ionomer restorative cement on vital tooth structure

The study was carried out on twenty-one contralateral pairs of caries free, premolars, that were indicated for extraction in conjunction with orthodontic treatment. The study was carried out on a Human male ranging in age from 12-22 y. Three different restorative reinforced glass ionomer cements were investigated two of them were commercial (chelon silver and legend silver) and experimental stainless-steel reinforced one. Three groups each formed of seven persons, the right side premolars used as control and the left side premolar received the investigated material. The experimental and its control tooth were extracted after four weeks of placement the filling materials. The enamel samples in the control and experimental teeth was obtained and prepared for x-ray diffraction analysis, then the teeth were prepared for histologic study. The x-ray diffraction analysis of the enamel samples revealed that, the intensity of fluorapatite was highest in the legend silver group, and the stainless-steel group was less than legend silver but higher than control and chelon silver specimens. Subsequently, the order of fluoride release was L > E > Ch & C. The histologic finding of this study showed that all the reinforced glass ionomer materials under investigation were non irritant to pulp tissue.     

Pulpal response to a resin-modified glass-ionomer material on nonexposed and exposed monkey pulps

OBJECTIVE: This study evaluated the biocompatibility of a resin-modified glass-ionomer material on monkey pulps. METHOD AND MATERIALS: Standardized Class V cavities were prepared in 112 teeth distributed in six healthy adult monkeys. The resin-modified glass-ionomer cement was placed in 24 nonexposed and 36 exposed pulps according to manufacturer's instructions. ZOE was used as a control in nonexposed pulps, while calcium hydroxide was used as a control for exposed pulps. Tissues were collected at 6 to 7, 21 to 27, and 90 to 97 days. After demineralization, the teeth were serially sectioned, stained, and observed by light microscopy. RESULTS: Except for one resin-modified glass-ionomer pulp at 6 days, there were no differences between the responses of nonexposed pulps to resin-modified glass-ionomer specimens and ZOE controls. In exposed pulps, eight of 36 resin-modified glass-ionomer pulps showed various grades of inflammatory response, all associated with stained bacteria. Pulpal healing was similar in both resin-modified glass-ionomer and calcium hydroxide direct-capped exposures. Twenty-two of 26 exposed pulps restored with the resin-modified glass-ionomer cement showed dentin bridge formation at 21 and 97 days. CONCLUSION: The resin-modified glass-ionomer material exhibited acceptable biologic compatibility in exposed and nonexposed cavities.     

A double-blind comparison of the efficacy and safety of milnacipran and fluoxetine in depressed inpatients

External root resorption is one of the most exasperating and least understood clinical problems in orthodontics. Numerous studies have been conducted, attempting to establish the factors causing root resorption of permanent teeth. Considerable variation exists however, in the extent and distribution of root resorption, seen in the orthodontic treatment of apparently similar cases. After an excellent review of the literature, Brezniak and Wassertein (1993) concluded that the most significant disgnostic aid in predicting whether root resorption would occur during orthodontic treatment, is the radiographic evidence of root resorption before treatment. A case is reported, describing the dilemma of orthodontically treating a patient, who had previously experienced trauma to the upper right central incisor, leading to external root resorption.     

Fluoride distribution in dentine and cementum in human permanent teeth with vital and non-vital pulps

Twenty-two selected permanent teeth [11 with vital pulps and 11 with non-vital (necrotic) pulps] were obtained from patients aged from 20 to 73 yr in Nagoya, Japan. Fluoride (F) profiles in tooth samples were examined by using an abrasive micro-sampling technique. F levels in the pulpal dentine were significantly higher in vital than non-vital teeth for each age group, although there were observed increases of F with age. In the cementum the F levels were strongly related to age and there were few differences in profiles and levels of F between vital and non-vital teeth. It was concluded that vital pulp is an important factor for the pulpal dentine to absorb fluoride.     

Advanced lightwire functionals reduce orthodontic relapse factor

Past orthodontic research by Schwarze in "Expansion and Relapse in Long Follow-Up Studies" concluded "... that orthodontically induced transverse sizes of the dental arches are very unstable." The article further stated that, "the majority of patients showed a decrease of the transverse molar and canine distance from the end of treatment to the follow-up examination." Also emphasized was the fact that "prolonged retention periods do not prevent relapses." These findings are based on orthodontic techniques that focus on movement of teeth and maxillary expansion without regard for existing cranial base and cranial bone distortions.     

Involvement of delta- and mu-opioid receptors in the potentiation of brain-stimulation reward

Human, dog, cat and rat dental pulps were investigated for the presence and distribution of galanin-like immunoreactive (-IR) nerve fibers, and the possible origin of pulpal galanin-IR nerve fibers in the rat was examined. Galanin-IR nerve fibers were present in the dental pulps of all species examined. Two types of galanin-IR nerve fibers were distinguished with regard to morphology; thin varicose nerve fibers and thick smooth-surfaced nerve fibers. Thin varicose galanin-IR nerve fibers were seen to run along the blood vessel in the human, dog and cat root pulp. In the coronal pulp, galanin-IR nerve fibers ran toward the odontoblastic layer but they did not form the subodontoblastic nerve plexus. In rat molar pulp, few galanin-IR nerve fibers were observed; the distribution of these nerve fibers was similar to those in human, dog and cat pulp. In contrast, many thick smooth-surfaced galanin-IR nerve fibers were observed near the blood vessels in incisor pulp of the rat; occasionally a few varicose galanin-IR nerve fibers were also observed. Transection of the inferior alveolar nerve or mandibular nerve caused complete disappearance of galanin-IR nerve fibers in rat dental pulp, while surgical sympathectomy of the superior cervical ganglion did not affect their distribution. The present results indicate that galanin-IR nerve fibers are present in the mammalian dental pulp, and that the intrapulpal galanin-IR nerve fibers in the rat originate from the trigeminal ganglion and are primary afferents.     

De novo protein synthesis by bovine uterine tube (oviduct) epithelial cells changes during co-culture with bull spermatozoa

Polypeptides secreted by uterine tube epithelial cells (UTEC) may facilitate sperm cell capacitation in vivo. This experiment evaluated the effect of sperm-UTEC co-culture on de novo protein synthesis by epithelial cells of the tubal isthmus. Comparisons of the patterns of proteins secreted into medium were made between four culture groups incubated for 24 h in the presence of 35S-methionine: group 1, sperm cells alone; group 2, control UTEC monolayers; group 3, UTEC co-cultured with sperm cells; and group 4, UTEC partitioned by a diffusible membrane from sperm cells during culture. Two-dimensional PAGE followed by fluorography was used to analyze conditioned medium containing secreted proteins from each group. The experiment was replicated four times. Sperm cells alone secreted no detectable proteins, whereas control UTEC monolayers produced a wide array of polypeptides. Sperm cells attached to UTEC in co-culture within minutes, and the resultant protein profile for these UTEC differed markedly from that of the control UTEC. Several new proteins were seen only from co-cultured cells, whereas other protein groups that were present with UTEC alone were absent in the co-culture medium of group 3. The protein pattern expressed by UTEC partitioned from sperm cells (group 4) was intermediate between that of the group 2 controls and that of co-cultured UTEC (group 3). In summary, the attachment of sperm cells to the UTEC during co-culture changed the types and quantities of proteins secreted into the conditioned medium as compared to those of control UTEC monolayers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Indications for compensatory extractions in orthodontic space closure in the frontal segments

This follow-up study presents patients who underwent orthodontic space closure in the maxilla after traumatic loss of frontal teeth or aplasia of a lateral incisor. Comparison covers findings obtained from casts and cephalograms in 24 patients with or without compensatory extraction. The findings indicate that acceptable results regarding axial tooth positioning and profile can be obtained without compensatory extraction. Prerequisites are distal occlusion of the first molars by one premolar width and continuous monitoring for regular overbite and uncrowded lower incisors. If orthodontic space closure can be achieved only by compensatory extraction, the indication for this space closure procedure calls for even more critical judgement.     

Immunohistochemical localization of endothelin-1 in placenta and fetal membranes in term and preterm human pregnancy

A case is reported in which an intruded incisor was initially treated by an endodontic dressing with calcium hydroxide and then extruded using a removable orthodontic appliance. A follow-up examination seven years after completion of endodontic therapy and bleaching showed a favourable response. A review of the relevant literature indicates that intrusion occurs in five to twelve per cent of luxation cases. In this type of injury maximum damage occurs to the pulp and all supporting structures because the tooth is driven into the alveolar process. Complications which have been reported include: pulp necrosis, apical radiolucencies, partial or total pulp calcification, root resorption (surface, inflammatory or replacement), marginal periodontal bone breakdown, and arrested or disturbed root development. The prognosis for pulp survival after intrusion is much more favourable for teeth with incomplete root formation than for teeth with complete root formation. Treatment options available to bring an intruded tooth into alignment are: to await spontaneous re-eruption which may occur if root formation is incomplete, uncovering of the intruded crown, orthodontic extrusion which is allied with gentle luxation if the tooth does not move, and immediate surgical repositioning.     

Recombinant human osteogenic protein-1 induces dentin formation: an experimental study in miniature swine

It was the aim of the present study to investigate the induction of dentin formation by recombinant human osteogenic protein-1 (hOP-1). In 4 adult miniature pigs a total of 16 teeth with artificially exposed dental pulps were capped with 3 mg of a complex of recombinant hOP-1 in collagen matrix (2.5 micrograms/mg), collagen matrix alone, or calcium hydroxide paste. Teeth were removed in block section after a healing period of 5 weeks. Decalcified sections were processed for light microscopy and histomorphometric analysis. In hOP-1 treated teeth substantial amounts of hard tissue formation (osteodentin and tubular dentin) had consistently led to a complete bridging of the defects. Less dentin formation was seen after calcium hydroxide application. In control defects collagen matrix alone failed to form complete dentin bridges. Recombinant human osteogenic protein-1 in a collagen carrier matrix appeared to be suitable as a bio-active capping agent for surgically exposed dental pulps.     

Bilateral projection of the canine tooth pulp to bulbar trigeminal neurons

Unit activity was recorded extracellulary from neurons of the cat medulla following electrical stimulation of the ipsilateral and/or contralateral cannine tooth pulps. The majority of the cells (67%) were only responsive to ipsilateral stimulation. However, many (28%) responded to stimulation of either canine pulp and a few (5%) responsed to contralateral stimulation alone. The neurons were localized histologically in the necleus proprius of the rostral trigeminal nucleus caudalis (NVCaud) and in dorsal portions of the ventromedially contiguous lateral reticular formation (LRF). Cells exclusively responsive to ipsilateral stimuli had a relatively wide dorsoventral distribution. In contrast, 'bilateral' and 'contralateral' cells were situated only in the deep NVCaud-LRF border zone or in immediately adjacent portions of the LRF. Generally, ipsilateral stimuli evoked response bursts with shorter latencies, more spike potentials and briefer interspike intervals than equivalent contralateral stimuli. In experiments designed to study afferent interactions, a conditioning stimulus, applied to either the ipsilateral or the contralateral canine, preceded a test stimulus applied to the other canine at predetermined interstimulus intervals. Responses to the test stimulus were either totally or partially suppressed when intervals of moderate duration (90-500 msec) were used. However, responses to the test stimulus frequently were enhanced when the intervals were breif (less than or equal to 60 msec) or when the teeth were stimulated simultaneously. The results reveal that bilateral afferents from the pulps of the canine teeth converge upon neurons of bulbar trigeminal structures, that the neurons are differentially responsive to the activation of ipsilateral and contralateral pulpal receptors and that bilateral afferent barrages originating in the canine pulps interact to modulate the firing patterns of the neurons.     

Mental nerve paresthesia associated with a non-vital tooth

Apical periodontitis is a common development associated with teeth with necrotic pulp. Although rare, some cases may present further complications, such as neuropathies in areas adjacent to the affected tooth. A case is described in which mental nerve paresthesia was associated with a non-vital mandibular premolar. Endodontic therapy resolved the paresthesia completely without further clinical complications.     

Thymidine phosphorylase (platelet-derived endothelial cell growth factor), microvessel density and clinical outcome in hepatocellular carcinoma

BACKGROUND/AIMS: Angiogenesis plays an important role in tumor growth and metastasis. It is regulated by angiogenic factors. Thymidine phosphorylase (platelet-derived endothelial cell growth factor) is one such factor. Although the significance of platelet-derived endothelial cell growth factor has been studied for several types of tumor, the expression of platelet-derived endothelial cell growth factor and its correlation with microvessel density or clinicopathological factors in hepatocellular carcinoma are unknown. We evaluated microvessel density and platelet-derived endothelial cell growth factor expression in hepatocellular carcinoma to determine whether microvessel density and platelet-derived endothelial cell growth factor expression are correlated with the clinicopathological factors of hepatocellular carcinoma. METHODS: Using immunohistochemical staining with anti-platelet-derived endothelial cell growth factor antibody and the ELISA method, we evaluated the correlation among platelet-derived endothelial cell growth factor expression, microvessel density and clinicopathological factors in 84 hepatocellular carcinoma patients. Microvessels were stained with anti-human von Willebrand factor (anti-Factor VIII) and anti-CD34. RESULTS: In the surrounding liver, there was a significant correlation between microvessel density and platelet-derived endothelial cell growth factor expression (p=0.002), and hepatitis C virus-positive livers had higher microvessel densities than otherwise (p=0.003). However, this correlation was not found for hepatocellular carcinoma, but hepatitis C virus-positive tumors had higher expression of platelet-derived endothelial cell growth factor (p=0.018). Microvessel density in hepatocellular carcinoma obtained by Factor VIII staining inversely affected the recurrence-free survival rate (p=0.0416), but the microvessel density by CD34 staining was not a significant predictor. CONCLUSIONS: This study indicates that platelet-derived endothelial cell growth factor may not be a major regulator of angiogenesis of hepatocellular carcinoma, but this enzyme may play an important role in hepatocarcinogenesis cooperating with hepatitis C virus. Also, the density, not of sinusoid-like vessels, but of larger vessels in hepatocellular carcinoma could be a prognostic factor for hepatocellular carcinoma.     

Computerized 3-D reconstruction of two "double teeth"

"Double teeth" is a root malformation in the dentition and the purpose of this study was to reconstruct three-dimensionally the external and internal morphology of two "double teeth". The first set of "double teeth" was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3-D reconstruction included serial cross-sectioning, photographs of the sections, digitization of the photographs, extraction of the boundaries of interest for each section, surface representation using triangulation and, finally, surface rendering using photorealistic effects. The resulting three-dimensional representations of the two teeth helped us visualize their external and internal anatomy. The results showed: a) in the first case, fusion of the radical and coronal dentin, as well as fusion of the pulp chambers; and b) in the second case, fusion only of the radical dentin and the pulp chambers.