Claudin rather than occludin is essential for differentiation in rat incisor odontoblasts.

Many morphological and developmental studies have demonstrated the characteristics of tight junctions (TJs) between odontoblasts. However, detailed localization of TJ-associated proteins in odontoblasts and their functions has not yet been clarified. To elucidate the relationship between the establishment of TJ structures and the differentiation of odontoblasts during early dentinogenesis, we studied the expression and localization of constituent proteins of TJs (claudin-1, occludin, ZO-1 and ZO-2) between odontoblasts in rat lower incisors using Western blotting, immunofluorescence and immunoelectron microscopy. When the expression of claudin-1 increases at the distal portion of mature odontoblasts, the TJs form complex networks of strands, and odontoblasts differentiated by developing distal membrane domains and by secreting specific molecules for mineralization. We conclude that the TJs of odontoblasts may play an important role in the differentiation of odontoblasts in rat lower incisors during early dentinogenesis.

Cell death during tooth eruption in the rat: surrounding tissues of the crown.

We investigated the occurrence of apoptosis and other types of cell death around the crown during tooth eruption of the rat upper molar. The TdT-mediated-dUTP-biotin nick end labeling (TUNEL) method and transmission electron microscopy (TEM) were employed. Apoptosis was detected by both TUNEL and TEM in part of the reduced enamel epithelium and connective tissue in the resorbing bony crypt of the pre-erupted tooth. In TEM, a large number of cells showed condensed chromatin and membrane-bound small bodies (apoptotic bodies). Macrophages that phagocytosed apoptotic bodies could be detected. Based upon the distance between bone surface and these apoptotic cells, and the characteristics of their organelles, we suggested that the apoptotic cells might be osteocytes, bone-lining cells (osteoblasts), and macrophages. We surmised that the osteoclasts had also died. Cells which contained autophagic vacuoles and autophagosomes, and others whose cytoplasm had dissolved, were also frequently observed. No progressive cell death was found in the oral epithelium or the fibrous connective tissue over the crown. These results suggest that apoptosis gives rise to some cell death during tooth eruption, but that other types of cell death also occur in various cells.

Gastrointestinal diseases and halitosis: association of gastric Helicobacter pylori infection.

The relationship between gastrointestinal conditions and halitosis is discussed. Few reports have suggested that gastrointestinal diseases may cause halitosis. H. pylori infection, which causes gastric ulcers, is considered as a possible cause for halitosis. Intensity of malodour of mouth air was found to be higher in H. pylori-positive patients than in negative patients. The levels of hydrogen sulphide and dimethyl sulphide in mouth air were also significantly higher in the positive patients than in the negative patients (P<0.05). When odour strength in exhaled breath was compared between the two groups, no significant difference was found. Hence, H. pylori infection might not cause a systemic condition producing breath odour. Although there were no significant differences in periodontal parameters or tongue coating between the positive and negative groups, H. pylori may be a frequent contributor to the production of malodour even though its role had not been suspected before. Further study would be necessary to clarify the reason for the increase of volatile sulphur compounds (VSCs) level in H. pylori infection.

Case report of lateral crossbite. Part I. Mixed dentition.

Lateral crossbite on mixed dentition does not always cause facial asymmetry or functionally abnormal movement of the mandible in children. However, it is often observed that facial asymmetry will worsen during growth in the absence of orthodontic treatment. In adult cases, lateral crossbite is one of the etiological factors of temporomandibular joint disorder. This case report presents two cases of lateral crossbite of mixed dentition. The terms of treatment were shorter than those in cases with permanent dentition. Also, methods of treatment were simpler, and the patients developed favorably. The opposite results were obtained in cases of permanent dentition.

Mandibular gingival arteriovenous malformation in pregnancy.

Arteriovenous malformations (AVM) are rare in the oral and maxillofacial regions. We report a case of a mandibular gingival AVM in a pregnant woman, who presented at 35 weeks' gestation with massive pulsatile bleeding from a mass in the mandibular gingival margin, which could be managed by local compression and cauterisation. After delivery, the mass gradually regressed. She developed a similar swelling during a second pregnancy. It was thought that increased cardiac output as a result of her pregnancy caused her AVM to progress.

Oro-maxillofacial development in patients with GH deficiency and in normal short children.

Detailed oro-maxillofacial studies using dental cast, pantomogram and cephalogram were performed in 43 patients with GH deficiency aged 7-17 years and compared statistically to the results from 62 short children with normal GH secretion. The dental age was retarded as compared to the chronological age in patients with GH deficiency by a mean of 2.0 +/- 1.3 years. This value did not differ statistically from that observed in normal short children (1.7 +/- 0.8 years). However the bone age was significantly retarded in patients with GH deficiency (3.2 +/- 1.7 yrs vs 1.5 +/- 1.1 yrs, p less than 0.001). There was no difference between tooth size or cephalogram analysis results in the children in the two groups. The coronal arch length, basal arch width and basal arch length were shorter in patients with GH deficiency. These data indicate underdevelopment of the maxilla in patients with GH deficiency.

Heat shock proteins in the human periodontal disease process.

The production of HSP by periodontopathic Gram-negative bacteria was examined by SDS-PAGE, two dimensional gel electrophoresis, and Western blotting using monoclonal antibodies against HSPs. Strains of Actinobacillus actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Prevotella intermedia, Prevotella nigrescens, Prevotella melaninogenica, and Treponema socranskii species produced HSP which reacted with anti-Yersinia enterocolitica HSP 60 and/or mycobacterial 65-kDA HSP monoclonal antibodies. It found that gingival homogenate samples from patients with adult periodontitis reacted with anti-human HSP were also found in a serum sample from a periodontitis patient. The present study suggests that HSPs are implicated in human periodontal disease process.

Cell proliferation and death of Hertwig's epithelial root sheath in the rat.

Hertwig's epithelial root sheath (HERS) degenerates immediately after root dentin is formed. However, odontogenic tumors or cysts may originate from residual cells, although little is known about how HERS proliferates and disappears. This study investigated whether cell death is provoked in the tissues surrounding the root during eruption of the rat upper molar. We employed the TdT-mediated-dUTP nick end labeling (TUNEL) method and transmission electron microscopy (TEM) to observe the morphological features of cell death. We examined the activity of cell proliferation immunohistochemically using proliferative cell nuclear antigen (PCNA) and the continuity of HERS using polyclonal keratin antibody (PK). Cell death resembling apoptosis and apoptotic bodies phagocytosed by neighboring mesenchymal cells were detected in only a few cells by both TUNEL and TEM. We also found cells with electron-lucent cytoplasm which contained dilated or ruptured mitochondria and remarkably dilated rough endoplasmic reticulum (rER) which lay sparsely along the root. These cells seemed to be dead HERS cells based on their ultrastructural features, location, and stage. PCNA-positive cells were found in the apical end of the HERS cells, fibroblasts of the periodontal ligament, and odontoblasts. PK reacted with HERS; however, PK-positive cells partially disappeared after the 15th postnatal day when the root dentin had formed slightly. These results may indicate that HERS cells migrate into the periodontal ligament or die immediately after root dentin is formed and that various types of cell death such as apoptosis and cytoplasmic type occur in the tissues surrounding the root during tooth development.

Relationships between the onset of pustulosis palmaris et plantaris, periodontitis and bacterial heat shock proteins.

Relationships between the onset of pustulosis palmaris et plantaris, periodontitis and heat shock proteins were studied by using enzyme-linked immunosorbent assay to examine levels of immunoglobulin G (IgG) against Escherichia coli GroEL, a recombinant DnaJ of Actinobacillus actinomycetemcomitans heat shock protein, a synthetic peptide made from the 180th to the 188th amino acids of Mycobacterium bovis BCG Hsp65, and a recombinant human Hsp60, in sera obtained from 43 pustulosis palmaris et plantaris patients judged to have chronic infectious diseases of the oral cavity. We found that the titers of IgG against E. coli GroEL and A. actinomycetemcomitans DnaJ in the sera from pustulosis palmaris et plantaris patients were significantly higher than those in the control group, whereas the titers of IgG against the synthetic M. bovis Hsp65 and the recombinant Hsp60 did not differ significantly. Periodontal therapy and extraction of teeth with periapical infectious resulted in remission of pustulosis palmaris et plantaris and a statistically significant reduction in the levels of IgG against E. coli GroEL in 9 of the 22 patients (41%) examined. We also found that the IgG levels against A. actinomycetemcomitans DnaJ in 6 serum samples of 16 (37%) were reduced, but not significantly, after the treatment. These results suggest that the IgG responses to heat shock proteins partially induced by oral bacteria may be related to the onset of pustulosis palmaris et plantaris in some patients.

Oro-maxillofacial development in patients with Turner's syndrome.

Detailed oro-maxillofacial studies using dental casts, pantomograms and cephalograms were performed in 28 patients with Turner's syndrome and compared statistically to the results from 23 normal short children. Small tooth crown size, short tooth roots and advanced dental age were characteristic of patients with Turner's syndrome. However, the incidence of peg shaped teeth, malocclusion, high arched palate and congenital anodontia were not characteristic of patients with Turner's syndrome. The coronal arch width (C.A.W.) and basal arch width (B.A.W.) were greater and the coronal arch length (C.A.L.) and basal arch length (B.A.L.) were less in patient's with Turner's syndrome. These data indicate underdevelopment of the maxilla in the forward direction forming the wide-, flat-shaped facial characteristic of patients with Turner's syndrome.