The purpose of this study was to clarify the effect of ethanol on rat molar tooth development. Pregnant rats were fed 25%-ethanol solutions or ethanol-free water up to delivery, and tooth germs, as well as fully developed teeth, obtained from the offspring (ethanol-exposed rats or control rats) were subjected to morphometric analysis and immunohistochemistry. No significant differences were observed in terms of tooth size between the ethanol-exposed and control rats. Moreover, no abnormalities in cusp number, form or dental surface structure was noted in the ethanol-exposed rats. In the ethanol-exposed rats, the tooth development showed a slight retardation in comparison to the controls. Morphological alteration in tooth germs was not observed in the experimental rats. Both bone morphogenetic protein-4 and basic fibroblast growth factor-2 were immunolocalized in the cells composing the tooth germs in the ethanol-exposed rats. No differences, however, were found in immunostaining intensity between the ethanol-exposed and control rats. Taken together, the results indicate that the effect of ethanol on tooth development was weaker than expected in the rat FAS model.

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BACKGROUND: Several local and systemic symptoms have been associated with teething in infants. AIM: To determine the symptoms associated with infant teething and related practices among Mbagala residents in Dar es Salaam, Tanzania. METHODS: A cross sectional descriptive study involving 200 mothers with their children aged 6-36 months. A structured questionnaire was used to inquire on the local and systemic symptoms associated with teething and measures taken by the parents in the event their children get those symptoms. Data entry and analysis was done using an SPSS program version 11.0. RESULTS: Ninety-seven percent of the participants believe that teeth emergence is associated with some systemic disturbances, mostly recurrent fevers (83.5%) and diarhoea (73%). Other often associated symptoms were runny nose (17.5%), increased body temperature (16.5%) and excessive salivation/drooling (11.9%). Sixty percent of the parents stated that their children had suffered some symptoms related to teething. Most of them were sent to hospital for management or were given self medication. CONCLUSION: The results of this study show that fever, diarrhoea, gingival swelling, gum irritation and redness are the symptoms often associated with teething. Most of the children who had suffered teething symptoms were taken to hospital.

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This study aimed to clarify the morphological characteristics of the fused portion in the mandibular fused deciduous anterior teeth using microfocus x-ray computerized tomography, a method which allows non-destructive three-dimensional observation at high resolution in any direction. The specimens consisted of five mandibular deciduous central/lateral incisor fused teeth, and four lateral incisor/canine fused teeth. These specimens were scanned using x-ray micro-CT and three-dimensional images of anatomical features of the crowns were reconstructed. Two-dimensional sliced images were created and then, the morphology of the fused portions were examined by measuring angle of the fused portion, enamel and dentin thickness at the fused portion. Angles of lingual fused portion in deciduous central/lateral incisor fused teeth, and labial fused portion in deciduous lateral incisor/canine fused teeth are significantly smaller, and the enamel thickness at these fused portions are also thinner. The values of the dentin thickness in deciduous central/lateral incisors tended to be thinner than those of deciduous canine, which means dentin thickness of the deciduous central/lateral incisors are thinner than that of canine. The fused portions in the fused deciduous anterior teeth have the similar morphological features to those of pit and fissure of the occlusal surface in molars and are likely to be the initiation and predilection sites of dental caries. Therefore, it is considered to be preferable to apply pit and fissure sealant into the fused portions at an early time point of the treatment.

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The aim of the study was to measure three-dimensionally using the semiconductor laser to examine changes in palate section areas, palate projection areas and palate volumes for 5-year olds children with maxillary protrusion of primary dental arch induced by finger sucking. Because of pressure by fingers on the palate, the palate section areas between deciduous canines and between primary first molars in finger sucking children were greater than those in children with normal occlusion. The palate projection area in the anterior segment of the arch in finger sucking children was greater than that in normal occlusion children. The anterior palate volume in finger sucking children was greater than that in normal occlusion children. However, because of anterior traction of the palate by fingers in finger sucking, the palate section area between the posterior margin of the primary second molars in finger sucking children was smaller than that in normal occlusion children. The palate projection area between posterior segment of the arch in finger sucking children was smaller than that in normal occlusion children. The posterior palate volume in finger sucking children was smaller than that in normal occlusion children.

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Inflammation in dental pulp tissue is associated with tissue degradation, and matrix metalloproteinases (MMPs) are believed to participate in this destruction. Elevated levels of some MMPs have been reported in inflamed pulp and periapical lesions. Moreover, in inflamed pulp, many kinds of inflammatory cytokines such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α, are released from inflammatory cells like macrophages, lymphocytes and neutrophils. In the present study, we examined whether TNF-α affected the production of MMP-2 in deciduous dental pulp fibroblasts and its signaling pathways utilizing gelatin zymography and western blotting analysis. TNF-α increased the expression of MMP-2 in a dose-dependent manner in deciduous dental pulp fibroblasts. LY294002 and Wortmannin, which are PI3-K (phosphoinositide 3-kinase) inhibitors, inhibited the MMP-2 production induced by TNF-α in deciduous dental pulp fibroblasts. Moreover, in deciduous dental pulp fibroblasts cultured with TNF-α, AKT (protein kinase B) was phosphorylated in a time-dependent manner with the maximum phosphorylation at 30 min, and LY294002 and Wortmannin abolished this phosphorylation of AKT in TNF-α-stimulated deciduous dental pulp fibroblasts. These results suggest that TNF-α may enhance pulp tissue destruction during pulp inflammation in part by regulating MMP-2, and that the AKT pathway is involved in MMP-2 production in deciduous dental pulp fibroblasts.

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Dental pulp plays an important role in tooth vitality. Previous studies have indicated that stem cells can be isolated from dental pulp, and dental pulp exfoliated from deciduous teeth has become a useful alternative for dental tissue engineering because of its higher proliferation rate. In the present study, we analyzed the differences in gene expressions between human dental pulps exfoliated from deciduous and permanent teeth by DNA microarray assays. A scatter plot of mRNA levels based on fluorescent signals in human dental pulps from deciduous and permanent teeth indicated a dispersed distribution pattern. In a scatter plot of the genes, 2,573 genes were expressed at > 2-fold higher levels in dental pulp from deciduous teeth, compared with permanent teeth. To confirm the microarray results, insulin-like growth factor-binding protein 5 (IGFBP5) and vascular endothelial growth factor A (VEGFA) showing higher mRNA expression levels were selected and analyzed for their mRNA levels by RT-PCR. Both the IGFBP5 and VEGFA mRNA levels were upregulated by about 3-fold in dental pulp from deciduous teeth compared with permanent teeth. Thus, the RT-PCR results for these genes were consistent with the microarray data. The dental pulps in deciduous and permanent teeth differ significantly with regard to their developmental processes, tissue structures and functions. The present findings using DNA microarray analyses to detect differences in the gene expressions of deciduous and permanent teeth may be useful for dental pulp tissue engineering.

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Although the occurrence of natal/neonatal teeth is a rare condition, we consider important clinical problems confronting pedodontists treating cleft lip and palate (CLP) infants. In daily clinical practice of the Pediatric Dental Clinic of Kyushu University Hospital, a high frequency of natal/neonatal teeth in CLP infants was observed. The objective of this study was to determine the prevalence of these anomalies in 55 CLP infants, who registered at the Hospital for 1 year 9 months from December of 2006 to August of 2008. As for distributing of the type of CLP among 55 infants, 39, 10 and 6 infants were unilateral, bilateral CLP and isolated CP, respectively. The prevalence of natal/neonatal teeth found in this study was 9.1% (5/55) in 55 CLP infants. Of these, 30% (3/10) were observed in bilateral CLP and 5.1% (2/39) were unilateral CLP. No natal/neonatal teeth were found in isolated CP infants. Further, all the cases were found in the maxilla except for one case. Thus, natal/neonatal teeth appeared at high frequency in CLP infants.

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The relationship between children’s deciduous dentition occlusal balance and body’s gravity center movement was studied. The participants of this study were 128 children with Hellman’s Dental Age IIA stage at a nursery school. The distance and the area of gravity center movement (GCM) when the participants had their eyes-opened and eyes-closed were measured with automatic posture analytical devices. Occlusal abilities including occlusal contact area, average pressure, maximum occlusal pressure, occlusal force and occlusal balance were measured with the Dental Prescale^® system. Analysis of occlusal balance was determined by separating the middle group (|x| ≤ 5 mm) from the deflection group (|x| > 5 mm) based on the position of occlusal balance center. A significant difference was found between the occlusal balance of the middle group (n = 96) and the occlusal balance of the deflection group (n = 32) in the distance and area of gravity center movement with eyes-opened and closed. The distance and area of gravity center movement of the middle group was less than that of the deflection group. Analysis of body balance was determined by the good balance group and bad balance group based on the GCM area with eyes-closed. A difference was found between the good balance group and the bad balance group in the occlusal contact area and occlusal force. The occlusal contact area and occlusal force of good balance group were higher than the bad balance group. Body and occlusal balance was observed to have some interactive influence during Hellman’s Dental Age IIA period. The influence of occlusal balance on body balance is much stronger and obvious than the influence of body balance over occlusal balance. Occlusal balance can influence on the body balance most of the time while body balance can sometimes influence on the occlusal balance.

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Posterior cross bite in the primary dentition causes not only functional disorders in jaw movements but also maxillofacial asymmetry. Previous reports have demonstrated a functional relationship between the stomatognathic system and middle ear. The purpose of this study was to investigate the association between cross bite and middle ear function. Thirteen children with posterior cross bite (mean age 5.3 years) and 10 children with normal occlusion (mean age 5.5 years) in the primary dentition were examined. The size of the primary tooth crowns and primary dental arches was measured in dental models. The middle ear compliance was measured on a tympanogram using Impedance Audiometer SI-50I (Morita Co.). Differences among the measured values of Static Compliance, Pressure, and Ear Clearance in the left and right ears were computed as absolute values and the pattern of tympanograms observed. The following results were obtained: (1) There was no significant difference in the mesiodistal width of the primary tooth crown. In the cross bite group, the arch width of maxilla was smaller than that of the normal Japanese standard of 5-year-olds. (2) Regarding the pressure, there was significant difference between children with posterior cross bite and normal occlusion. (3) Regarding tympanogram, in the normal group, 90% showed symmetrical Type A (normal range for tympanogram) on both sides, and in the cross bite group, 53.8% showed symmetrical Type A and 7.7% showed Type As (restricted tympanogram) on both sides. Type C (retracted tympanogram) indicating eustachian tube abnormality was not seen in the normal group, however, in the cross bite group, it was seen in 7.7% of the right and 23.1% of the left side ears. (4) There was no correlation between incisor midline shift and the pressure. It was concluded that children with posterior cross bite were at a significantly increased risk for middle ear dysfunction.

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Tooth size directly affects abnormalities in dental occlusion, and is decided by genetic and environmental factors. Malalignment of teeth occurs as a result of discrepancies in jaw bone and tooth size. In this study, F₂ mice acquired by crossing C57BL/6J (B6) strain having large mesiodistal tooth crowns and MSM strain having small mesiodistal crowns were used to conduct quantitative trait locus (QTL) analysis and to identify chromosomes involved in determining mesiodistal tooth size. Analysis revealed that the QTL responsible for tooth size could be mapped chromosomes 3 and 17 in mice. Therefore, we measured mesiodistal crown length of the first molar of the mandible, and analyzed candidate chromosomes that decide the size of teeth in vivo using consomic mice between B6 and MSM strains. Mesiodistal crown length was largest in consomic mice of B6-Chr.3^MSM, thus some genes for mesiodistal crown development may be located on chromosome 3.

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Our previous study showed that inbred mice strains such as C57BL/6CrSlc (B6) and C3H/HeSlc (C3H) revealed high and low caries susceptibility, respectively. Quantitative trait locus (QTL) analysis was performed by a genome-wide scan on genetic crosses of B6 and C3H mice. The analysis showed that two effective values, one significant QTL was found on chromosome2, and the other suggestive QTL was detected on chromosome8. For the elucidation of the causative genes of dental caries susceptibility, we constructed mice termed consomic mice (B6-Chr.2^C3H), in which the chromosome2 derived from B6 was replaced by that of C3H. For establishment of consomic mice, 2nd generation mice were obtained by mating B6 and F1 (B6×C3H). Microsatellite markers were used during confirmation of the genomic recombination. The recombination mice showing heterozygous genotype on the whole chromosome2 were crossed to the next generation continuously. Until the 13th generation, the mice were continuously genetically crossed by backcross and the genotype of all chromosomes was checked. The selected mice of the 13th generation were checked for heterozygous genotype of B6 and C3H on chromosome2, and whether all were homozygous for B6 on all chromosomes except chromosome2 and finally B6-Chr.2^C3H were established by intercrossing the selected mice of 13th generation. We established consomic mice that can be used as an experimental model for investigating the causative genes of dental caries susceptibility.

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In a retrospective cross-sectional study, dental development of 1,620 healthy Japanese children, aged 3-15.9 years, were evaluated by the Demirjian method. A subset of 55 pantomograms were randomly chosen and re-examined. The intra-class correlation coefficient on maturity scores was 0.99. The Cohen’s Kappa coefficient to agreement stage by teeth and overall agreement by stage resulted in average 0.85 and 0.82 respectively, both interpreted as “substantially reliable”. The children were classified by sex and age. In each age group, dental age and chronological age was compared using paired t-test. Most of age groups were overestimated and had a significant difference. New standards for Japanese children were built using a logistic curve with the equation y = 100*{β/(1+e^-α(x-x0))} as a basis. A residual analysis was made to verify if the curve was appropriate. The explained variance for the regression curve resulted in 94.25% for males and 95.07% for females. For both sexes, a linear regression line between chronological and estimated dental age showed 94% of association. The Demirjian standards were not suitable for the present-day Japanese children, so it was necessary to establish specific standard.

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Flowable resin restoration is a useful technique for children with caries. However, when composite resin restoration is performed by an inexperienced clinician, improper placement technique can lead to such problems as poor adaptation, voids and secondary caries formation. In this study, we examined fluoride release from surface of pre-reacted glass-ionomer (S-PRG) fillers containing flowable resin, termed flowable giomer. Beautiful Flow F02 showed a higher amount of fluoride released during the experimental period as compared with the other flowable resins tested. We also used that flowable giomer for Class I, II, and III restoration procedures in 95 primary teeth and 85 permanent ones, and evaluated the results using USPHS/Ryge criteria. Beautiful Flow F02 showed good clinical properties equal to those of conventional resin restorations previously reported. Our results indicate that a flowable giomer is useful for primary and permanent teeth esthetic restoration, which is important for the prevention of secondary caries and adhesion of bacterial flora on resin surfaces.

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The purpose of this study was to determine the time-window of infection for Streptococcus mutans between mother and child in Japan and which factors affected colonization by this microorganism. After obtaining informed consent, saliva was collected from the mothers and their children. These samples were serially diluted and inoculated onto Mitis-Salivarius agar and Mitis-Salivarius bacitracin plates, and then cultured under anaerobic conditions at 37°C for 5 days. Isolated mutans streptococci were identified by conventional biochemical characteristics and species-specific polymerase chain reaction based on the dextranase gene. No mutans streptococci groups were isolated from 0-5-month-old children with no erupted teeth. No statistically significant difference was found in detection rates in S.mutans among mother’s milk, bottled milk or mixture. Cross-sectional study revealed that detection rates of S.mutans in the saliva samples increased with number of erupted teeth. Pulse-field gel-electrophoresis patterns obtained from isolated S.mutans using SmaI from the mothers and their children indicated that colonization by S.mutans in some Japanese children resulted from vertical transmission. In strains in which vertical transmission was observed, the mutacin IV and Smb A and B genes were detected from 8 out of 12 isolates. These results suggest that the window of infection for S.mutans is at around 6-23 months, and that colonization by this microorganism is mainly affected by number of erupted teeth.

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Hypohidrotic ectodermal dysplasia (HED) is an inherited disorder characterized mainly by hypotrichosis, hypohidrosis, a characteristic facial appearance, hypodontia/anadontia and malformed teeth. The aim of this study was to assess the pattern of missing teeth and tooth malformations in children affected with HED in Istanbul, Turkey. Clinical and radiological findings of 16 children (9 boys and 7 girls) diagnosed with HED attended the clinics of Pediatric Dentistry, Istanbul Univ., were reviewed; the pattern of missing and malformed teeth in primary and permanent dentition was evaluated. Percentages of children affected with anadontia, oligodontia and hypodontia were found as 12.50%, 81.25% and 6.25%, respectively. The most frequently missing teeth were noted as primary lateral incisors (27.48%) in the primary dentition and lateral incisors and second premolars in the permanent dentition. A pattern of symmetry was assessed for agenesis of teeth. Peg shaped/tapered and conical morphology was observed in total of 11 primary and 10 permanent teeth. Radiological examination exhibited root abnormalities in 13 teeth. Girls showed higher frequency of root malformations; and no significancy was found in data of prevalences of agenesis and crown tooth malformations regarding gender. Data of missing and malformed teeth in both dentition of children with HED has emphasized the need of early multidisciplinary treatment options for dental and psychological rehabilitation.

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The purpose of this report was to describe an unusual severe ectopic eruption of the bilateral maxillary canines in a young patient aged 7 years and 8 months and to discuss the effects of early intervention such as extraction of the predecessors and fenestration of the affected canines. The patient was referred to the author’s clinic for a consultation regarding bilateral ectopically erupting maxillary canines with an ectopic maxillary right first molar. After improvement of the first molar, the affected canines were fully erupted and aligned in occlusion 3 years and 7 months after the extraction of primary canines. Before treatment, the findings on the orthopantomogram were as follows, there was no direct cause, both canine tooth germs were situated in very high positions, and the cusp tips of both canines were not overlapped with the roots of the adjacent lateral incisors (Sector 1). The maxillary left canine impacted horizontally in a mesio-distal direction (axial angulation: 90 degrees) could be successfully guided to eruption by early intervention such as the extraction of predecessors and three fenestrations. Even in severe ectopic cases, therefore, it is considered that traction may be postponed until no effect of fenestration can be detected in cases of early discovery and intervention when the crown top is situated in Sector 1.

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A case of impacted tooth due to the presence of an odontoma identified in a 5Y7M-old girl is presented. An intraoral examination showed that the maxillary right second primary molar had not emerged into the oral cavity, while a periapical X-ray photograph revealed a small round radiopaque mass with a diameter of approximately 2 mm. The calcified mass was suspected to interfere with eruption of the affected tooth and enucleation of the tissue was carried out under local anesthesia. Histopathological examination results showed that the calcified mass consisted of dental enamel, odontogenic epithelium, and pulp-like tissue, and it was diagnosed as an odontoma. At 6Y1M of age, the tooth had not emerged into the oral cavity due to the possibility of interference in the distal cervical area of the adjacent first primary molar or that of strong tension of the gingiva above the affected tooth. Thus, fenestration of the gingiva over the impacted tooth crown was performed and the tooth crown of the affected tooth appeared in the oral cavity at the age of 6Y6M.

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A 10-year-and-4-month old girl was shown to have inverted maxillary right second primary molar and permanent successor teeth, after being referred to our clinic for examination of an unerupted maxillary right second primary molar. Orthopantomograph images taken at the age of 7Y4M showed an impacted maxillary second primary molar and ambiguous tooth germ of its permanent successor, while images obtained at the age of 10Y4M exhibited the tooth germ of the permanent successor in a position on top of the impacted primary molar. Orthopantomographs were obtained twice during the next year, which showed development of the second premolar. The dental age of the entire dentition, except for the maxillary right second premolar, at 7Y4M was considered to be consistent with her chronological age, whereas it was approximately 6 months to 1 year behind of chronological age when determined at the age of 10Y4M, 11Y4M, and 12Y3M. The dental age of the permanent second premolar gradually increased, however, remained approximately 4 years behind chronological age. At 12Y3M, computed tomography examinations were performed to clarify the three-dimensional positions of the second primary molar and its permanent successor. At that time, the impacted primary molar was located close to the inferior part of the maxillary sinus, while the tooth germ of the permanent successor was located in the apex region of the adjacent first permanent premolar and first permanent molar. We decided to carry out the periodical examinations to observe the maxillary right second primary molar and premolar.

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A case of idiopathic external root resorption identified in a girl aged 4 years and 2 months (4Y2M) is presented. The patient visited our clinic with a chief complaint of spontaneous pain in the area of the lower left primary canine. An intraoral examination revealed severe mobility of the affected tooth, while its marginal gingiva was swollen with a maximum periodontal pocket depth of 5 mm. Irrigation of the periodontal pocket and general administration of antibiotics relieved the symptoms within 1 week. However, spontaneous pain recurred in the same area at 5Y0M. External root resorption was found with alveolar bone loss on the distal side, and microbiological analyses using broad-range polymerase chain reaction and sequencing methods were carried out with saliva and subgingival dental plaque specimens. In dental plaque specimens from unaffected regions and saliva specimens, Neisseria and Streptococcus species were frequently identified throughout the observation period. On the other hand, Prevotella and Fusobacterium species were predominant species in the dental plaque specimens from the area of the affected tooth. These results indicate that periodontopathic bacterial species rarely seen in children may have inhabited periodontal pockets formed from external root resorption in the present case.

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The aim of the present study was to examine the prevalence rate and treatment outcome of maxillary canine transposition in Japanese children according to the conventional standard and our new additional consideration of the classification. From 140 cases with ectopic canines diagnosed in the Pediatric Dental Clinic of Niigata University Medical and Dental Hospital, we selected 10 transposition cases as the present subjects. Out of 10 cases, 4 were males and 6 females. Six were classified into type A: the mesio-distal positional interchange of the canine and the first premolar, 2 cases into type B: the mesio-distal transposition of the canine and the lateral incisor, and the other 2 cases into type C: the present new classification that showed the vertical transposition of the canine and the first premolar within the developmental bone. The prevalence rate of types A and B resembled the previous papers regarding the ratio of sex and bilateral occurrence. Although 3 cases in type A, one case in type B and one case in type C could finally be aligned in the normal tooth order, every one of the types A and B cases were aligned in the reverse order. For every one case in types A and C, the transposed canines were extracted. It is recommended that pediatric dentists take an orthopantomogram during early mixed dentition as a routine practice in order to detect anomalies of tooth eruption, such as tooth transposition, as early as possible.

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Dens evaginatus (DE) is a developmental malformation characterized by the presence of an extra cusp or tubercle. Dens invaginatus (DI) is also a dental anomaly found in tooth where the outer surface folds inward. Although each configuration was a rare developmental dental anomaly, the concurrence of DE and DI in a single tooth is an extremely rare. Those anomaly teeth are clinically significant due to the susceptible to dental caries or the possibility of the pulpal disease such as pulpitis and necrosis pulps without clinical history. Therefore, it is important to prevent further worse complications through the early diagnosis and intervention. Here we report that a clinical case of DE and DI concurrently affecting the mandibular central incisor in a 6-year-old Japanese girl, along with a pertinent review of the literature.

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We treated a rare case with multiple sites of idiopathic internal resorption in primary dentition. A 3-year-old Japanese boy with no history of medical or dental disorders was referred by a general dentist for management of multiple sites of internal resorption in the primary teeth. Those with internal resorption had a pinkish color, however, no symptoms were noted. An X-ray photographic examination revealed round radiolucent lesions in the crown pulp of the upper right first primary molar, as well as in the roots of the lower right primary canine, upper left central primary incisor, and lower right lateral primary incisor. A histological examination of pulp removed from the right lower lateral primary incisor revealed increases in blood vessels, lymphocytes, and macrophages, while odontoclasts were not identified. Resorption of the teeth progressed rapidly and the lower right primary canine spontaneously exfoliated. Thereafter, endodontic treatment using Vitapex^® halted the progress of tooth resorption. Our findings showed that early diagnosis, endodontic treatment, and short-interval follow-up examinations are needed to preserve teeth from rapid internal root resorption.

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Dental alterations of number are the most common congenital anomaly in humans however concomitant tooth agenesis and supernumerary teeth are very rare in the general population. Therefore, the aim of this present work is to report an unusual family case with a heterogeneous dental anomaly phenotype and to discuss the craniofacial developmental biology and human genetics of these concomitant dental anomalies.

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