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Purpose The present survey examined the need for dental treatment for caries among Cambodian children as well as the living environments of such children. Then, based on the results we assessed whether education programs aimed at caries prevention are required in Cambodia. Methods Between 2010 and 2012, 1893 children (age: 3, 5, or 12 years), who were living in Siem Reap Province or Phnom Penh, the capital of Cambodia, were subjected to oral examinations and a survey. Then, the relationship between the prevalence of caries among the children and living environment factors was examined based on the survey data. Results There was no significant difference in the prevalence of caries between Siem Reap Province and Phnom Penh. The mean prevalence rate of caries and the children's mean df tooth index (dft) and decay-missing-filled tooth (DMFT) scores were higher than those seen in Japan in all age groups. The proportion of treated teeth was low in all age groups, which suggested that a number of children had not consulted dentists. Many of the children regularly ate snacks containing sugar, which are closely associated with caries. Conclusion Providing dental health education for parents and appropriate brushing advice for children would probably reduce the incidence of caries among Cambodian children. It is necessary to establish systems for preventing dental disorders in Cambodia as promptly as possible.

Background Periodontal ligament (PDL) healing and long term prognosis of replanted avulsed teeth should rely on several factors including length of extra-oral dry time and type of the storage medium. The status of periodontal ligament is critical for the healing of replanted teeth. Different substances have been used for root surface treatment to promote formation of PDL and increase the survival of avulsed teeth submitted to replantation. Aim The purpose of this study was to assess the effect of recombinant basic fibroblast growth factor 2 (bFGF) and enamel matrix derivative (EMD) on root resorption after delayed replantation. Design 18 freshly extracted single-rooted incisor and premolar teeth were extracted from the beagle dogs and immersed in whole bovine milk for 45 and 60 min (n = 3 each). Following storage period, sockets washed and teeth were treated with bFGF and EMD and replanted into the sockets. After 8 weeks, dogs were sacrificed, specimens processed to 4-μm thick serial sections for histopathologic examination and morphometric assessments. Thus, the proportions of the roots that exhibited signs of surface resorption, inflammatory resorption, and replacement resorption, that is, ankylosis and normal PDL were noted. Results The percentage of root resorption was in the following order: EMD>milk>bFGF for 45 min and milk>EMD>bFGF for 60 min. For all groups, teeth stored 60 min showed significantly higher incidence of PDL resorption than those stored for 45 min (P

EL/Sea mice are characterized by 100% incidence of agenesis of the third molars (M3). In a previous study, chromosomal mapping of the ninth generation EL/Sea congenic strains revealed a major locus for agenesis of M3, designated am3, in the 125–137 Mbp region of chromosome 3. In the present study, to determine the precise location of the am3 locus, we produced further generations of the EL/Sea congenic strains for am3 in which the restricted interval on chromosome 3 of EL/Sea was replaced by a MSM/Msf-derived homolog. The eleventh generation congenic mice that were either heterozygous or homozygous for the MSM/Msf-derived interval exhibited a significant decrease in the incidence of M3 agenesis (p < 0.00001). Results confined the am3 locus to an interval of 1 Mbp on chromosome 3, demonstrating that Lef1, one of the essential transcription factors for early tooth development, is the strongest candidate for am3.

We measured the face breadth and the maxillary arch width of a total of 230 mice from 21 SMXA recombinant inbred (RI) mouse strains and their parental strains SM/J and A/J, and investigated genetic factors associated with these parameters. The coefficient of variation between maxillary arch width and face breadth within the same strain was low, suggesting that this is strictly governed by genetic factors. Maxillary arch width and face breadth exhibited a continuous size distribution within the 23 strains, suggesting the involvement of multiple genes rather than a single gene. In the 21 strains of SMXA RI mice and strains SM/J and A/J, there was a significant correlation between face breadth and maxillary arch width in male mice, with a correlation coefficient of 0.52. We performed a genome-wide scan for quantitative trait loci (QTL) determining maxillary arch width and face breadth. With respect to face breadth, the logarithm of odds (Lod) score for D11Mit229 on chromosome 11 was significant for both males and females, suggesting that the genes determining face breadth are located in this region. Although no loci exhibiting a significant Lod score were detected for maxillary arch width, the highest Lod scores were detected for the same loci as for face breadth. These findings suggest that some of the genes that determine face breadth may be the same genes that determine maxillary arch width.

Tooth agenesis is the most common developmental anomaly of the human dentition. Epilepsy-like disorder (EL) mice, which have a 100% incidence of agenesis of the third molars, may be a good model for the genetic study of human tooth agenesis. Our previous congenic breeding strategy using EL mice confined a major locus for agenesis of M3, designated am3, within an approximately 1 Mega base pair (Mbp) interval on chromosome 3, which contains five known genes; Lef1, Hadh, Cyp2u1, Sgms2 and Papss1. The aim of this study was to identify the strongest candidate for am3 among the five genes using real-time PCR analysis. The tooth germs of M3 in the bud stage of EL and control mice were dissected out, and total RNA was extracted. In real-time PCR analysis, a significantly low level of expression of Lef1, which is one of the essential transcription factors for early tooth development, was observed in M3 of EL mice. In addition, a significantly low level of expression of Fgf4, which is a direct transcriptional target for LEF1 in early tooth development, was observed in M3 of EL mice. Our results suggest that the cause of M3 agenesis of EL mice may be a low level of Lef1 expression in M3 in the bud stage of EL mice.

The purpose of the present study was to determine whether different consistency of diet and malocclusion induced by the extraction of molar teeth on the masticatory organs modulated gastric acid secretion, gastric emptying and intestinal transit in young and elder rats. Male Wistar rats (young, 5weeks; elder, 1.5years) were used in this experiment, and were divided into 2 groups. Group one (G1) was maintained with solid diet, Group two (G2) with mud diet. Further, the mandibular molar teeth of G2 were extracted. The experimental period was 10weeks. The effect of aging and malocclusion on the parameters of gastric secretion was examined using pylorus-ligated rats. The gastric emptying rate (GER) and small intestinal transit rate was determined in rats by evans blue from the stomach and charcoal from the small intestinal, respectively. In pylorus-ligated rats, Young-G2 rat of gastric juice volume, acid output and pepsin secretion remarkably showed significant decrease in comparison with Young-G1 group, but there was not significant difference between Elder-G1 and Elder-G2. GER of Young-G2 rat group was 44.2±7.9%, significantly lower than that of Young-G1 rat group (61.6±8.8%, P

Multiple supernumerary molars are an uncommon occurrence. In this case report, six molars were observed unilaterally in the maxilla of a 7-year-old patient. An erupted supernumerary molar was found palatal to the permanent upper right first molar. On computed tomogram examination, four unerupted molars were clearly identified distal to the permanent upper right first molar. This dental anomaly is rarely encountered and this may be the first case in which four supernumerary molars were observed in a quadrant with no identifiable pathology.

Although using Buckley's Solution of formocresol (FC) in pulpotomy procedures is becoming less common in pediatric dentistry. This study measured concentrations of formaldehyde (FA) evaporated during fixing and investigated safe procedures for FC pulpotomy. Methods: Ten measurements were taken for each of the conditions described below. Locations measured for each condition were 1) at a position equivalent to the patient, 2) at a position equivalent to the dentist, and 3) at a position equivalent to the assistant dentist. Condition 1 used no peripheral equipment. Condition 2 used an intraoral air evacuator, Condition 3 used extraoral air evacuators, Condition 4 used both extraoral and intraoral air evacuators. At the patient's FA levels were 0.414 ppm during Condition 1, 0.158 ppm during Condition 2, 0.252 ppm during Condition 3, and 0.091 ppm during Condition 4. FA levels at the dentist were 0.115 ppm during Condition 1, 0.042 ppm during Condition 2, 0.081 ppm during Condition 3, and 0.028 ppm during Condition 4. FA levels at the dental assistant were 0.067 ppm during Condition 1, 0.038 during Condition 2, 0.059 ppm during Condition 3, and 0.025 ppm during Condition 4. Exposure concentrations of FA during FC pulpotomy might have using of an extraoral, intraoral air evacuator during FC pulpotomy reduces formaldehyde exposure to patient, dentist, and dental assistant.

The aim of this study was to identify the chromosomes harboring candidate causative gene(s) for dental attrition using pools of DNA from two strains mice with different susceptibilities to attrition. Attrition scores in F2 mice aged 260 days obtained by genetic crossing of C3H/HeJSlc and C57BL/6JSlc mice ranged from low to high. DNA from four F2 mice with high attrition scores and four F2 mice with low attrition scores was pooled. The 53 Mit markers used in this study were determined as informative markers, being polymorphisms between C3H/HeJSlc and C57BL/6JSlc, and were distributed among all auto chromosomes in mice. This suggests that the candidate chromosomes harboring causative gene(s) for attrition are linked with D4Mit13 and D13Mit9, which were identified as homozygous alleles of C3H in Pool High DNA and homozygous alleles of C57BL/6 in Pool Low DNA.

Hypophosphatasia (HPP) is an inherited systemic skeletal disease caused by mutations in the gene encoding the tissue-nonspecific alkaline phosphatase (TNALP) isozyme. The clinical severity of HPP varies widely, with symptoms including rickets and osteomalacia. TNALP knockout (Akp2−/−) mice phenotypically mimic the severe infantile form of HPP; that is, TNALP-deficient mice are born with a normal appearance but die by 20 days of age owing to growth failure, hypomineralization, and epileptic seizures. In this study, a lentiviral vector expressing a bone-targeted form of TNALP was injected into the jugular vein of newborn Akp2−/− mice. We found that alkaline phosphatase activity in the plasma of treated Akp2−/− mice increased and remained at high levels throughout the life of the animals. The treated Akp2−/− mice survived for more than 10 months and demonstrated normal physical activity and a healthy appearance. Epileptic seizures were completely inhibited in the treated Akp2−/− mice, and X-ray examination of the skeleton showed that mineralization was significantly improved by the gene therapy. These results show that severe infantile HPP in TNALP knockout mice can be treated with a single injection of lentiviral vector during the neonatal period. © 2011 American Society for Bone and Mineral Research.

In pediatric dentistry, examination of the development of crown or tooth root is essential to determine the physiological development age. Measurements of the tooth size and dental arch width are also required to predict normal occlusion and oral function, and to plan appropriate dental treatment. Some dental anomalies are keys to identify congenital malformation syndromes. In patients with behavioral disorders, it is quite difficult to take diagnostic dental models and pantomographs, since patient co-operation and stability in body movement for a few minutes is necessary while taking the dental impression and pantomographs. For patients with severe mental retardation and behavioral disorders, performing computed tomography under general anesthesia or deep sedation is easier than taking pantomographs while awake. The aim of the present study was to compare the tooth development stage on pantomographs and mesiodistal diameter measurements of tooth size and dental arch width of dry human skulls with the images of those on 128 multi-detector row computed tomography (MDCT). Based on the results, the measurements of tooth development stage, tooth size and dental arch width on MDCT images were clinically precise.

Proper understanding of the orofacial development and deformities associated with various syndromes is important for planning appropriate dental treatment and improving the craniofacial features. However, it is quite difficult to take cephalometric radiographs of patients with severe mental retardation or behavioral disorders, since patient co-operation and stability of body movement are necessary while taking the radiographs. Computed tomography (CT) is potentially a better tool for the diagnosis and treatment planning of complex maxillofacial deformities than conventional lateral cephalograms. CT images of patients with mental retardation can be taken under general anesthesia. The absorbed dose of radiation in 128 slice multi-detector row computed tomography (MDCT) used in this study is established as CTDI vol. 17.24 mGy, which is less than that of conventional CT (65 mGy). However, the use of MDCT for cephalometric analysis in pediatric dentistry has not been reported. Hence, the aim of the present study was to compare the reliability and difference of angle and linear measurements of craniofacial form using the landmarks on conventional and MDCT lateral cephalograms of human skulls. The results of this study showed that angular and linear measurements recorded from conventional and MDCT lateral cephalograms were similar. In conclusion, there were no significant differences in the mean and standard deviation of angular and linear measurements between conventional and MDCT lateral cephalograms of human skulls. Angular and linear analysis on MDCT cephalogram might show good precision for craniofacial analysis.

In this work, we examined the culture condition of alveolar bone marrow multipotent mesenchymal stromal cells (ABMMSCs), aiming to apply regenerative therapy to older periodontitis patients. To better understand the character of cultured cells from alveolar bone marrow, the expression profiles of well-known genes and their responses to the induction of osteogenic, chondrogenic, or adipogenic differentiation were examined. Using αMEM-based culture, ABMMSCs could be obtained from older individuals than in previous reports. Interestingly, ABMMSCs expressing Klf4 were able to differentiate into osteoblasts. The prediction of differentiation potential by Klf4 could be a useful guide for further improvement of the culture conditions required to culture ABMMSCs derived from older individuals. J. Cell. Biochem. 107: 1198–1204, 2009. © 2009 Wiley-Liss, Inc.

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 presentday Japanese children, so it was necessary to establish specific standard.

X-linked anhidrotic (hidrotic) ectodermal dysplasia (EDA) is characterized by absence or the deficient functions of hair, teeth and sweat glands. The temperature adjustment of EDA is difficult in the state of the high temperature. We investigated whether this air-conditioning clothing (Kuchofuku ® ) was effective to the patient with EDA. It was revealed that the patient's body surface and deep body temperatures rose in spite of gentle exercise without air-conditioning clothing, and that when they used it, although their deep body temperature slightly rose during exercise, their body surface temperature did not rise. It also suggested that, not only patients with EDA, but also the people who have trouble in perspiration can widen their sphere of daily activities by using it.

Hypodontia of permanent teeth was evaluated from orthopantomograms of 2072 apparently healthy pediatric patients at The Hospital of Nihon University School of Dentistry at Matsudo. The prevalence of congenitally missing teeth (CMT) was 8.7% in boys and 10.8% in girls, and 9.4% for both sexes combined. Most cases (67.8%) involved either one or two missing teeth. There were in total 574 CMT, and on average 2.8 teeth were missing per child. The most commonly absent tooth was the mandibular second premolar. On the other hand, no first molars were missing in any case. A high frequency of CMT mandibular incisors (18.82%) was observed, and this seems to be a characteristic peculiar to individuals of Asian ethnicity. Oligodontia (6 or more CMT excluding the third molar) ranged from 6 to 14 teeth, with a prevalence of 1.4% in general: 1.8% for girls and 0.9% for boys. Symmetry of CMT was predominant: 214 pairs for bilateral symmetry and 107 pairs for symmetry between two antagonistic quadrants. The distribution of CMT between maxillary and mandibular hypodontia in the right and left quadrants for boys and girls no had significant association (P < 0.05).

The purpose of this study was to investigate the mutagenic and antimutagenic interactions between several fractions of saliva and the habitual oral bacteria. Antimutagenicity was examined against the known mutagenic substances, 4-nitroquinoline-1-oxide (4NQO), AF-2 and benzo[a]pyrene (B[a]P)), using Salmonella typhimurium strains TA98 and TA100 in Ames test and Rec + and Rec − strains of Bacillus subtilis of Rec-assay. Four fractions from human saliva, whole saliva, supernatant saliva (Sup), precipitation in saliva (PPT) and heated saliva (Heat), were examined against 4NQO, AF-2 and B[a]P-induced mutagenicity. The whole saliva exhibited the strongest antimutagenic activity amongst all fractions applied against 4NQO and AF-2 in Ames test with more than an 80% inhibition rate. However, the whole saliva had an activity of only 50% inhibition against BP. The potency of the antimutagenicity was in the following order: whole saliva>Sup>PPT>Heat, in Ames test. Rec-assay also exhibited a pattern of antimutagenicity similar to that of Ames test. The cultured supernatants of the oral anaerobic bacteria exhibited a weak mutagenic potency. The cell wall skeletons of the oral anaerobic bacteria exhibited stronger antimutagenic activity against each mutagen than that of the oral aerobic bacteria.

Apatite is considered to be effective for bone regeneration when it contains calcium carbonate and β -TCP. In the present study, we made 3 different apatite preparations, hydroxyapatite, hydroxyapatite containing calcium carbonate, and hydroxyapatite containing β -TCP, using spark plasma sintering and compared their abilities for osteoinduction. For elucidation of bone regeneration, evaluations are generally made after euthanasia of experimental animals. However, the present R_mCT ® procedure allowed such evaluations while the animals were alive. Our results showed that sintered HAP containing β -TCP was more effective for guided bone regeneration than the other test materials.

In this study, we focused on the relationship between the morphological features of the articular eminence and the presence of the anterior disc displacement on MR image in youngsters. We classified the morphology of the articular eminence into four categories, flattened, sigmoid, box and deformed on MR image. The results of this study indicated that morphological features of the articular eminence on serial MR images were related to the articular disc configuration, which were the presence of the anterior disc displacement in the intercuspal position, the levels of the anteriorly displaced disc in the intercuspal position and the presence of the reductions of the anteriorly displaced disc in the maximum opening mouth position. There were statistically significant differences in the distribution of the morphology of the articular eminence between normal disc position and anterior disc displacement in all of three sagittal planes. There were statistically significant differences in the morphology of the articular eminence among the levels of the anteriorly displaced disc in central and lateral planes. There was statistically significant difference in the distribution of the morphology of the articular eminence between presences of reduction of the anteriorly displaced disc in the central plane. We concluded that the morphological feature of the articular eminence continuously changes as dental arch develops in the time with temporal instability of mixed dentition, and seems to have positive correlation to the anterior disc displacement.

OBJECTIVE: To investigate the maternal environment influence on cortisone-induced cleft palate in mice. METHODS: The A/WySn and the C3H/He strains of mice were used. Pregnant mice were injected on days 11 through 14 of gestation with 2.5mg/mouse/day of cortisone. The A/WySn, C3H/He, F 1 hybrids and N 2 backcross fetuses that attained at least day 18 of development were checked for the presence of cleft palate. RESULTS: The frequency of fetuses with cleft palate and the ratio of dams bearing fetuses with cleft palate in the A/WySn strain (40.6% and 67.7%) were both significantly higher than those in the C3H/He (16.7% and 44.4%), F 1 (12.4% and 47.1%) and N 2 (24.0% and 55.3%) mice. The highest frequency of cleft palate was observed when the litter size was 8 in A/WySn, 7 in C3H/He, 8 and 9 in F 1 , and 9 in N 2 , respectively. CONCLUSION: The results suggested that the reaction to cortisone-induced cleft palate is different from the A/WySn and C3H/He strains of mice. The A/WySn strain of mice was more susceptible than the C3H/He strain of mice. The data suggest that litter size might play a role in defining cleft palate frequency.

It is well understood that the application of a self-etching primer enhances the bonding at the resin-teeth interface. In this study, we designed a self-etching primer consisting of N-methacryloyl glycine (NMGly) and N-methacryloyl-2-aminoethyl phosphonic acid (NMEP). The demineralization effects on the hydroxyapatite or dentin by the carboxylic acid in the NMGly and by the phosphonic acid in the NMEP and their effects on the bond strength of the resin to the tooth were examined. The application of the NMGly-NMEP solution to the enamel resulted in an increase in the bond strength when additional amounts of NMEP were added to the NMGly aqueous solution. This increase was due to the phosphonic acid in the NMEP demineralizing the enamel. Conversely, the addition of the NMEP to the NMGly solution resulted in a decrease in the bond strength to the dentin. The optimal concentration of the NMEP in the NMGly-NMEP solution resulted in bond strengths of over 20 MPa for both the enamel and dentin.

Amelogenesis imperfecta (AI) is a group of commonly inherited defects of dental enamel formation, which exhibits marked genetic and clinical heterogeneity. The genetic basis of this heterogeneity is still poorly understood. Enamelin, the affected gene product in one form of AI (AIH2), is an extracellular matrix protein that is one of the components of enamel. We isolated three ENU-induced dominant mouse mutations, M100395, M100514 and M100521, which caused AI-like phenotypes in the incisors and molars of the affected individuals. Linkage analyses mapped each of the three mutations to a region of chromosome 5 that contained the genes encoding enamelin (Enam) and ameloblastin (Ambn). Sequence analysis revealed that each mutation was a single-base substitution in Enam. M100395 (Enam(Rgsc395)) and M100514 (Enam(Rgsc514)) were putative missense mutations that caused S to I and E to G substitutions at positions 55 and 57 of the translated protein, respectively. Enam(Rgsc395) and Enam(Rgsc514) heterozygotes showed severe breakage of the enamel surface, a phenotype that resembled local hypoplastic AI. The M100521 mutation (Enam(Rgsc521)) was a T to A substitution at the splicing donor site in intron 4. This mutation resulted in a frameshift that gave rise to a premature stop codon. The transcript of the Enam(Rgsc521) mutant allele was degraded, indicating that Enam(Rgsc521) is a loss-of-function mutation. Enam(Rgsc521) heterozygotes showed a hypomaturation-type AI phenotype in the incisors, possibly due to haploinsufficiency of Enam. Enam(Rgsc521) homozygotes showed complete loss of enamel on the incisors and the molars. Thus, we report here that the Enam gene is essential for amelogenesis, and that mice with different point mutations at Enam may provide good animal models to study the different clinical subtypes of AI.

I-cell disease is a rare autorecessive metabolic disorder that is classified as one of the lysosomal storage diseases. Gingival enlargement is a representative oral manifestation of patients with I-cell disease. This report describes a case with a satisfactory prognosis after gingivectomy for gingival enlargement accompanying I-cell disease in a 2-year-old boy. The chief complaints were both eating disorders and night terrors accompanied by gingival enlargement of both the maxillary and mandibular alveolar gingivae, especially in the region of the first deciduous molars. Although it was supposed that there were various hazards associated with gingivectomy caused by aortic incompetence, sigmoidal spinal curvature and hypertrophy of the laryngopharynx, gingivectomy with an internal bevel incision was performed under general anesthesia to improve the chief complaints. A piece of the enlarged gingivae dissected during the operation was examined histopathologically, and the histopathological diagnosis was gingival hyperplasia. The patient's signs and symptoms of the eating disorders and night terrors have improved since the gingivectomy operation. Recurrence of the gingival enlargement has not been identified up to 18 months after the surgery. It is therefore concluded that gingivectomy for gingival enlargement accompanying I-cell disease was effective for this 2-year-old boy.

Cleft lip with palate is a widespread disfiguring birth defect of complex and poorly understood etiology. The A/WySn mice are good models with which to study the genetic factors of cleft. Our previous study of mated the A/WySn and C3H/He strains found that cleft lip with palate occurred due to cortisone exposure in both the A/WySn and N2 backcross mice, but not in the C3H/He and F1 hybrid mice. These findings suggested that autosomal recessive genetic factors cause cleft lip with palate in the A/WySn strain of mice. Interval mapping should identify a candidate chromosome and the region that included the candidate gene(s) causing cleft lip with palate. The present study investigated informative DNA markers for interval mapping. We used 136 Mit (Massachusetts Institute of Technology) markers to amplify target DNA of A/WySn, C3H/He and F1 hybrid mice by PCR. Amplified DNA products were detected by direct gel analysis. We determined 82 informative markers that were distributed throughout the autosomal chromosome and which could detect polymorphisms between the A/WySn and C3H/He on gel. These results suggest that it is possible to perform the interval mapping for searching candidate chromosome including the loci responsible for cleft lip with palate in A/WySn mice using determined 82 markers.

The purpose of this study was to investigate whether the lesion of incipient caries was associated with morphological differences between the molars of C3H/HeJ and C57BL/6J mice. The caries scores for C57BL/6J and C3H/HeJ at 35 days old were 3.8±2.5 and 0±0 (mean±SD), respectively. The caries scores for C57BL/6J and C3H/HeJ at 49 days old were 42.4±8.3 and 4.2±2.4 (mean±SD), respectively. There was a 10-fold difference between C57BL/6J and C3H/HeJ in terms of caries progress. Incipient caries then appeared at the second fissure of lower M1. The central region of the second fissure of lower M1 in C57BL/6J was deeper and rougher than the same region in C3H/HeJ. The Ca/P ratios of the fissure for C57BL/6J and C3H/HeJ were 1.69±0.27 and 1.71 ±0.25 (mean±SD), respectively. The total data showed no significant difference between C57BL/6J and C3H/HeJ.In conclusion, it was found that incipient caries appeared at the second fissure of lower M1. Moreover, it is suggested that the morphology of the fissure as well as the immune responses may be responsible for the dental caries caused by stagnation of bacterial plaque.

Dental caries is a multifactorial, infectious disease with little known about the host genetic factors influencing susceptibility. This study aimed to identify the major candidate chromosomes for dental caries susceptibility and to detect the relevant regions within these. Quantitative trait locus (QTL) analysis was performed on genetic crosses of C3H/HeJ (caries-resistant) and C57BL/6J (caries-susceptible) mice inoculated with Streptococcus mutans serotype c. In a genomewide scan, three suggestive QTLs were detected on chromosomes 1, 2, and 7, one significant QTL was found on chromosome 2, and one highly significant QTL was detected on chromosome 8. The likelihood ratio statistic (LRS) was raised around the marker D1Mit21 in the middle region of chromosome 1, between D2Mit255 and D2Mit311 in the distal region of chromosome 2, and the region distal to D7Mit31 on chromosome 7. A significant QTL was located between the markers D2Mit237 and D2Mit101 on chromosome 2. The LRS was highly significantly raised between markers D8Mit208 and D8Mit280 on chromosome 8, and exceeded a highly significant level between markers D8Mit211 and D8Mit280. These results suggest that major gene(s) responsible for dental caries susceptibility or resistance are located in one or more of these regions.

We noted the absence of all 4 third molars (M3) in Epilepsy-Like disorder (EL) mice, an animal model for the study of epilepsy. This study was conducted to identify the major candidate chromosome and to detect the region that included the candidate gene causing the absence of M3 in EL mice. Linkage analysis was performed on genetic crosses of EL mice and MSM ( Mus musculus molossinus) strain mice, which had a normal complement of teeth. Genome-wide screening by individual genotyping of F2intercross mice identified mouse chromosome 3 as one of the candidate chromosomes. Based on high linkage scores in detailed genotyping of F2intercross and N2backcross mice, the candidate locus for the absence of M3 in EL mice was mapped on the middle of chromosome 3.

The purpose of this study was to compare the production of interleukin-1β (IL-1β) by peptidoglycan from Lactobacillus casei (L. casei) in human pulp-derived fibroblasts from deciduous (DHPF) and permanent teeth (HPF). DHPF and HPF were collected from 6 noncarious deciduous teeth (6-9 year-old individuals) and 6 noncarious permanent teeth (20-25 year old individuals) extracted in the course of orthodontic treatment. Both IL-1β protein production and IL-1β mRNA levels from peptidoglycan- treated DHPF and HPF were clearly enhanced, compared to IL-1β protein production and IL-1β mRNA levels from peptidoglycan-non-treated DHPF and HPF that were not treated by peptidoglycan. Furthermore, IL-1β protein production and IL-1β mRNA levels from peptidoglycan-treated DHPF showed clearly lower levels, compared with IL-1β protein production and IL-1β mRNA levels from peptidoglycan-treated HPF. These findings suggest that pulpitis in deciduous teeth was less induced than pulpitis in permanent teeth, and that L. casei- peptidoglycan stimulated IL-1β production through enhancement of IL-1β mRNA expression from DHPF and HPF.

The Ebk/MDK1 gene belongs to the receptor tyrosine kinase (RTKs) family and has been shown to be closely related to the Eph/Eck/Elk subfamily. A study was conducted to investigate the role of Ebk/ MDK1 in the oral development of early mouse embryogenesis. RT-PCR analysis identified the presence of Ebk/MDK1 mRNA in the region of the first molar at embryonic day 15 (E15). In situ hybridization analysis in the developing oral field from E12 to E16 revealed Ebk/MDK1 expressed in the mesenchyme underlying the dental epithelium of both of the first molars and incisors, as well as in the mesenchyme of the developing alveolar ridge, palate, tongue and lip. The distinct patterns of Ebk/MDK1 expression suggest that this gene may be involved in the establishment of these oral structures in mouse embryogenesis.

The purpose of this study was to identify the major candidate chromosome influencing susceptibility to dental caries in mice and to detect the region that contains it. Genetic factors affecting dental caries in mice were examined using two inbred strains of mice, C57BL/6J and C3H/HeJ, and these genetic crosses were inoculated with Streptococcus mutans serotype c (1.0 x 109 CFU/mouse). The caries scores for C3H/HeJ and C57BL/6J were 3.1±2.6 and 39.8±12.6 (Mean±S.D.), respectively. The mean caries score of the F1 hybrids was 17.6 ±13.2 (Mean±S.D.) which was in the range 1 to 46. The caries scores of F2 [(C57BL x C3H) x (C57BL x C3H)] mice had an extensive range from 0 to 68. These findings suggested that some genes play roles in caries development.Based on our results with the genetic crosses, we used F2 intercross mice to investigate candidate chromosomal linkages using DNA pooling methods and obtained a valuable linkage on chromosomes 2 and 17. Thus, we concluded that one of the candidate genes controlling the genetic difference for the dental caries promoting ability between C3H/HeJ and C57BL/6J might be located on chromosomes 2 and 17.

Summary A dual role of abscisic acid (ABA) in photoperiodic flowering of Pharbitis nil , cv. Violet was studied. ABA given before an inductive dark treatment lowered the flowering response without influencing the critical night length and the most effective time of a night break. ABA given after a dark treatment accelerated the transport of flowering stimulus and enhanced flower initiation response at shoot apex. Endogenous ABA level in cotyledons was determined by gas chromatography-selected ion monitoring. There was no remarkable difference between ABA levels under short-day and long-day conditions. Fluridone, an inhibitor of ABA biosynthesis, given before and during an inductive dark treatment affected flowering response only slightly. The results indicate that exogenous ABA inhibits the early phase of the flowering without influencing the time-measuring process, and promotes both transport of the flowering stimulus and flower-initiation process, although endogenous ABA plays little role in the regulation of flowering.

Abscisic acid (ABA) has been reported to have diverse effects on photoperiodic flowering. Activity of a natural ABA, (+)-(S)-abscisic acid (S-ABA), was recently suggested to be somewhat different from that of racemic ABA, which has been used in previous work. Use of S-ABA might enable clarification of the role of ABA in flowering. S-ABA inhibited flowering of the short-day plant Pharbitis nil (cv. Violet) when given before or 4 h after the start of a 14-h inductive dark period, and promoted flowering when given 12 h after the start of the dark period or later. The flower-promoting effect was observed when ABA was applied to the shoot apex. These results indicate that ABA has a dual effect on photoperiodic flowering of P. nil: it may inhibit the time-measuring process as well as promote some processes that proceed after generation of the flowering stimulus.

The influence on photoperiodic flowering of (2-chloroethyl)trimethylammonium chloride (CCC), an inhibitor of gibberellin (GA) biosynthesis, was studied in the short-day plant Pharbitis nil cv. Violet. The cotyledons contained high levels of endogenous bioactive gibberellins, whereas in the plumules and first leaves the levels were low or undetectable. The first leaf responded to a single dark treatment by inducing flowering when it was 10 mm or wider. Similar seedlings, but without cotyledons, were used as the assay plants to study the effect of CCC on photoperiodic flowering. Treatment with CCC had no effect on flowering of seedlings without cotyledons, although stem elongation was inhibited. By contrast, CCC inhibited flowering of the intact seedlings with cotyledons. Gibberellic acid applied to the shoot apex or to the first leaf promoted flowering in the CCC-treated seedlings without cotyledons. The results indicate that gibberellins are not essential for the flower induction process in leaves, but that they promote flower initiation and/or later processes in the shoot apices.

We report an application of the interval mapping technique using DNA pools of inbred mice. The latest challenge in molecular genetics is to use microsatellite markers for gene mapping and cloning. Little is known about the interval mapping technique for detecting candidate linkages in inbred mice. We investigated the optimum interval length of microsatellite markers for gene mapping using DNA pools on mouse chromosomes, and found that between 25 and 35 centi Morgans (cM) was sufficient. We estimated that at least two to four microsatellite markers required for interval mapping should be present on each chromosome. The number required would depend entirely on the linkage map.

MRL/l strain mice, which possess a lymphoproliferative gene inducing swelling of systemic lymph nodes, develop a SLE (systemic lupus erythematosus)-like syndrome at around 8 w of age. MRL/n mice, which carry 99.6% of the genes of MRL/l mice, lack the gene for lymphoproliferation and exhibit only a slight degree of lymph node swelling late in life. This study investigated whether the salivary immune response caused by Streptococcus mutans(S. mutans) infection prevented dental caries in MRL/l and MRL/n mice after 8 w of age. A total of 10 MRL/l mice and 10 MRL/n mice were fed a commercial pellet diet without sucrose until 74 d of age, and then fed Diet 2000 containing 56% sucrose ad libitum from 75 to 130 d of age. On d 75, both strains of mice were inoculated with S. mutans JC-2 for 7 d. At 130 d of age, saliva samples were collected and caries scores were assessed. The results obtained suggested that the salivary immune response was one of the most important factors regulating caries occurrence.

Cherubism is a rare autosomal dominant syndrome characterized by abnormal bone tissue in the lower part of the face. Mutations in the gene coding for SH3BP2 have been identified in about 80% of people with cherubism. The aim of this study was to determine whether a mutation in the SH3BP2 gene was the molecular basis of cherubism in two unrelated families.Two cases of the aggressive form of Cherubism were described in two Turkish families with extensive bilateral swelling in the mandible, typical pathological features and familial history. Genomic DNA was extracted from six affected and three unaffected individuals from two families, and mutations in the SH3BP2 were detected by PCR, and direct DNA sequencing was carried out.In the first family, a missense mutation Arg415Gln was found in exon 9 of the SH3BP2 in all affected individuals. The unaffected individuals did not have this mutation. In the second family, another missense mutation Pro418Thr was identified in exon 9 of the SH3BP2 in the patient and his mother with cherubism.We detected the point mutations in the SH3BP2 gene in the patients with multiple affected individuals. Genotype-phenotype association studies in individuals with cherubism are necessary to provide important knowledge about molecular mechanisms of the disease.

Inbred mice are a suitable material for genetic studies, and mandibular shape in particular provides a highly quantitative hereditary trait. We investigated which genetic trait in F1, F2 and N2 hybrid mice was most strongly affected by the presence of a large or small mandible in the parents. Ten C57BL/6By strain mice as parents with a small mandible and 10 MRL/n strain mice as parents with a large mandible were employed. Twenty-five (C57BL/6By male X MRL/n female) F1 and 67 F2 hybrids, and 28 (F1 male X C57BL/6By female) N2 backcross hybrids were obtained by laboratory mating. The inter-landmarks of the right mandible were measured by an electronic digitizer. Each mean value of horizontal dimensions in F1 mice resembled that in MRL/l mice, and that in N2 mice was intermediate between C57BL/6By and MRL/n mice. On the other hand, the mean values of vertical dimensions in F1, F2 and N2 hybrids were intermediate between those of C57BL/6By and MRL/n mice. Hence we suggest that horizontal dimensions are predominantly inherited by mice with a large mandible, and that vertical dimensions show intermediate inheritance between mice with large and small mandibles in the C57BL/6By and MRL/n strains.

We describe the dental and craniofacial anomalies of 2 ethnically distinct patients with Goldenhar syndrome, which is characterized by hemifacial microsomia, facial asymmetry, and ear and dental abnormalities. A 7-year-old Japanese girl and 12-year-old Turkish boy with Goldenhar syndrome were examined clinically and radiographically; both had symptoms of hemifacial microsomia. Multiple organ involvement can limit surgical correction of deformities and affect patient management. Therefore, long-term regular follow-up by a multidisciplinary team is important to monitor the growth and development of patients. (J Oral Sci 53, 121-124, 2011)

Supernumerary teeth are among the most common dental anomalies affecting the primary and permanent dentition. They are usually found in the anterior maxilla and occur infrequently in the primary dentition. The purpose of this paper was to report a case diagnosed with primary supernumerary tooth in the primary second molar region. The crown and root shape of the primary supernumerary tooth resembled that of the primary first molar. On radiographic examination, the primary supernumerary tooth was followed by a permanent supernumerary successor with an unusually big crown. The primary supernumerary molar was immediately extracted to avoid interference with the development of the second premolar's tooth bud. This dental anomaly is rarely observed, as only primary supernumerary teeth in the anterior region have been reported in the dental literature.

We tested the sensitivity of taste after reduction of the tongue in four girls with Beckwith-Wiedemann syndrome. No patient had taste blindness, but the ability to detect salty and bitter tastes declined after reduction of the tongue.

Tooth crown size may be determined by both genetic and environmental factors. The aim of this study was to identify quantitative trait loci (QTLs) affecting dental crown size and determine whether there is genetic independence between upper and lower teeth, using SMXA recombinant inbred strains of mice. Mesiodistal and buccolingual crown diameters (MD and BL, respectively) of the upper and lower first molars (M1 and M1, respectively) were measured. For each trait, mean values of substrains showed a continuous spectrum of distribution. Genome-wide scan detected QTLs exceeding suggestive threshold levels for MD of M1 (chromosomes 7, 13, and 17), BL of M1 (chromosomes 8 and 13), MD of M1 (chromosomes 7 and 13), and BL of M1 (chromosomes 3 and 15). These findings suggest that tooth crown size is controlled by multiple genes, and that there is some independence of genetic control between M1 and M1.

Predicting the mandible size before the termination of growth of the maxillofacial bones is essential in pedodontics as well as for the predictions needed for genetic analysis. Here, Quantitative Trait Locus (QTL) analysis was used to detect the chromosomal regions responsible for the mandible length between the menton and gonion in an SMXA recombinant inbred strain of mice. Around the region 60 cM from the centromere in chromosome 10, the logarithm of the odds score showed a higher than suggestive level. Around the regions 13 cM and 16 cM in chromosome 11, two significant QTLs were detected. Analysis of genotypes from loci corresponding to those QTLs revealed a large mandible when the region between the markers Hba and D11Mit163 and D10Mit70 and D10Mit136 indicated the genotype from the A/J and SM/J alleles, respectively. These results suggest that the major gene(s) responsible for mandible length are located in these regions.

We describe oral manifestations in six patients (three females and three males aged 6 to 24 years) with Kabuki syndrome (KS), based on their physical, orthopantomographic, and cephalometric findings. All six patients had a high-arched palate, malocclusion, most commonly unilateral posterior cross-bite (5/6), severe maxillary recession and mid-facial hypoplasia. Other frequently observed oral manifestations included small dental arch and hypodontia. Three patients lacked permanent teeth, mostly the central/lateral incisors. Both tooth size (in primary and permanent teeth) and dental arch (in length and width) tended to be small. We would like to stress that oral care and management is a must for the well-being of KS patients.