Various aspects of human growth and development have been reported to be adversely affected by malnutrition in early life. Opinion is still divided regarding the role of nutritional status in dental development. The study was carried out to determine the effect of breastfeeding pattern on the eruption times of primary teeth. The study population consisted of 1,013 clinically healthy babies, infants and preschool children between the ages 4-36 months who visited the immunization clinics at the Community Health Centres in Ife Central and Ife East Local Government Areas. Primary teeth erupted earlier in children who were exclusively breastfed when compared to those who were partially breastfed (P < 0.05). In most ages (months) children who were exclusively breastfed had more number of erupted teeth compared to those partially breastfed (P < 0.05). Within the limitation of this study, children who were exclusively breastfed had lower mean age of emergence in eighteen out of twenty teeth than those partially breastfed with ten teeth being statistically significant, showing that nutrition may play an important role in the emergence of primary teeth.

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Recently airway blockage accidents have increased in Japan, and airway blockage accidents involving children account for 12% of the total. However, the causes of airway blockage accidents are not clear. The oropharynx plays an important role in feeding and swallowing by helping to prevent aspiration and airway blockage accidents. Few studies, however, detail the changes in volume of the oropharynx during growth. The relationship, therefore, between the volume of the oropharynx and growth was investigated in this study. The subjects, 50 males and 50 females aged 7 to 15 years, were grouped according to a dental development age index (Hellman Dental Age), resulting in a dental development range from IIC to IVA. Cone beam computed tomography (CB Mercuray, Hitachi) was used to scan each subject’s head, and a three-dimensional modeling system was used to measure the oropharynx volume, height and other. The mean and standard deviation of the height of males was 35.48±6.85 mm and of females, 34.78±7.42 mm. In male and female subjects, the height of the oropharynx airway increased from IIC to IVA. The mean and standard deviation of the oropharynx volume of males was 5,570.79±3,790.30 mm³ and of females, 4,942.80±2,818.75 mm³. In male and female subjects, the volume of the oropharynx airway increased significantly from IIIC to IVA. Therefore, this study suggests that there is a strong relationship between the increase of the oropharynx airway and the time and condition of eruption of the second molar teeth from period of IIC to IVA of the Hellman Dental Age index.

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TiO₂ has an antibacterial effect against Streptococcus mutans (S.mutans). The objective of this study was to show the Inhibition of the adhesive ability of S.mutans on hydroxyapatite pellet using a toothbrush equipped with TiO₂ semiconductor and solar panel. Gradual brushing of 9 hydroxyapatite pellets was done by the same person using a solar toothbrush under 750/LUX light source in water. As a control, pellets brushed with a placebo toothbrush were done using the same procedure by the same person. All the pellets were inoculated in 10 ml Brain Heart Infusion (BHI) broth containing 100 μl of 10⁸ CFU/ml S.mutans and 1% sucrose and then incubated at 37°C for 12 hours. After incubation, the adherence conditions of S.mutans on each pellet were checked. The bacterial count of S.mutans on the brushed pellets using solar toothbrush were fewer than those using placebo toothbrush. The quantities of adherence of S.mutans decreased according to number of brushing and adhesion on pellets brushed more than 50 times could not be recognized. However, adhesion of S.mutans on the pellets brushed using placebo toothbrush were recognized and the adhesive quantities were visually the same. These results occurred because of some electronic charges on the brushed pellets using solar toothbrush. Soladey-3 toothbrush prevented S.mutans adhesion to the hydroxyapatite pellet under a light source.

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It has been reported that individual adults generally take consistently sized bites when eating the same food, while children do not. The present cross-sectional analysis was performed on 60 children and 20 adults to ascertain the age-related changes in the fluctuation in bite size and in the number of chews per bite. The subjects comprised four age groups (5-, 8-, and 11-year-old children and adults), with each group consisting of 10 males and 10 females. The subjects were instructed to take a bite of each of four test foods (bread, sausage, apple and rice), and they were allowed to chew and swallow as usual. After each bite, the remaining food was weighed to calculate the bite size. The fluctuations in bite size and in the number of chews were analyzed using coefficients of variation. The fluctuations in both bite size and the number of chews decreased with age, so that the 11-year-olds showed almost the same values as adults. The present results suggested that the physiological functions related to recognizing and consuming foods mature during early adolescence, when almost all permanent teeth have erupted. The present findings also indicated that the fluctuation in bite size might be an indicator of the maturation of masticatory function in children.

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In crown restoration, it is important to understand the internal anatomical feature of each tooth, as the morphology of human deciduous teeth is particularly complex. The purpose of this study was to clarify three-dimensionally the topographic relationship between the crown contour and the pulp chamber of the mandibular first deciduous molars using a micro-CT system. Fifteen mandibular first deciduous molars obtained from the dried skulls of Indian children in the deciduous dentition period were used as specimens. Three-dimensional reconstructed images were reproduced by combining the two-dimensional slice imaging data using a micro-CT system. Crown contours and shapes of the pulp chamber were observed from various directions. In addition, the thickness of tooth substance at each pulp horn was also measured. In observations of the topographic relationship between the crown contour and the pulp chamber, the pulp horn of the mesiobuccal pulp chamber was found to project the most to the cusp side. The distance between the pulp horn and enamel surface was also shortest (2.45±0.30 mm) in this region. Furthermore, in teeth with a deep, wide trigonid notch, the lateral wall of the mesiobuccal pulp chamber projected in the mesial direction. These results suggest that in preparation of cavities in mandibular first deciduous molars, close attention must be focused on pulp exposure in the pulp horn of the mesiobuccal pulp chamber. In addition, the lateral wall of the mesiobuccal pulp chamber should be noted in teeth with the deep, wide trigonid notch.

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The aim of this study was to determine the variation in mineral ions (Ca and P) concentrations in 2-day dental plaque taken from different areas of the deciduous and the permanent dentition that may be related to the caries status of tooth surfaces obtained from children and young adults. We also compared those minerals between the deciduous and the permanent dentition. Plaque samples were collected from eight dentition sites, including the upper-anterior-buccal (UAB) and -lingual (UAL), lower-anterior-buccal (LAB) and -lingual (LAL), upper-posterior-buccal (UPB) and -lingual (UPL), lower-posterior-buccal (LPB) and -lingual (LPL) regions. Significant differences among these eight different sites were determined from Ca and P ions concentrations, as well as the Ca/P ratio, calculated by ANOVA. Plaque associated with the LAL region closest to the main salivary ducts and that is less prone to caries, had significantly higher levels of Ca, P ions concentrations, a higher Ca/P ratio than any other dentition areas in both children and young adult subjects. Statistical differences were seen in minerals between children and young adults. Ca ion concentrations in dental plaque from young adults were significantly higher than those of children at the LAL site. Statistical analysis of the relationships between Ca and P ions showed that there were strong associations between Ca and P ions, especially in the UPB, LAL and LPL regions where there is a high exposure to saliva. We conclude that there is a site-specificity of plaque mineral content in both children and young adults, which may reflect the differences in exposure to saliva, resulting in differences in the local cariostatic challenge.

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The objective of the study was to make three dimensional measurements of the maxillary palate of 3- and 4-year old children who have developed anterior cross bite of deciduous dentition using a semiconductor laser. The effects of anterior cross bite were examined on the interdentition section area, the intradentition projection area, and the palate volume. Compared with normal occlusion, anterior cross bite of deciduous dentition caused smaller interdentition section areas at the deciduous canines and the primary first molars, and greater interdentition section areas at the primary second molars and between the posterior margins of the primary second molars. The intradentition projection area at the anterior dentition was smaller in anterior cross bite than in normal occlusion. The intradentition projection area at the posterior dentition in anterior cross bite was nearly the same as that in normal occlusion. The anterior palate volume was smaller and the posterior palate volume was greater in anterior cross bite than in normal occlusion. The above results suggest that anterior cross bite in deciduous dentition suppresses anterior growth and accelerates posterior growth of the maxillary palate.

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We investigated restitution processes in mechanically exposed rat molar pulp during pulpotomy with calcium carbonate (CC). The results of the CC treatment were then compared with Calvital^®-containing calcium hydroxide (CH). Micro-computerized tomography (micro-CT), hematoxylin and eosin (H&E) staining and immunoreactivity for nestin, dentin matrix protein-1 (DMP-1) and osteopontin (OPN) were also analyzed. The increment of dentin-like calcified tissue in the pulp was observed by micro-CT. Both CC and CH groups induced pulpotomy resulted in changes associated with inflammation followed by progressive odontoblasts differentiation, dentin matrix secretion and dentin-like bridge formation. Necrotic layer formation and moderate to severe inflammation occurred during the early stages in the CH group. Necrotic layer formation was not observed in the CC group and only associated with mild to moderate inflammation. Immunoreactivity of nestin was observed earlier in the CC group than the CH group. In the CC group, immunoreactivity of DMP-1 was identified beneath the amputated site after 7 days, before increasing until 28 days, and immunoreactivity of OPN was observed in the dentin-like bridge at 28 days, which was also similar to the CH group. These findings suggested that the primary processes of reparative dentinogenesis after pulpotomy with CC may involve natural pulpal wound-healing mechanisms that are similar to the restitution processes observed during pulpotomy with CH. However, CC may prove to be less irritation and more calcified tissue formation than traditional CH-based materials when used as a pulpotomy agent.

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The substances that cause physiological halitosis have been found to be mainly volatile sulfur compounds (VSCs) [hydrogen sulfide (H₂S), methylmercaptan (CH₃SH) and dimethylsulfide (CH₃)₂S] produced by putrefaction of anaerobic bacteria. In order to clarify the role of these periodontopathic bacteria in halitosis, we investigated the amounts of four species of bacteria, Prevotella intermedia, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in 10 μl of the tongue coats of healthy people using quantitative PCR and examined the correlation with the concentrations of VSCs present in the subject’s breath (physiological halitosis). The following results were obtained.
1. H₂S in the oral breath of the subjects showed a positive correlation with the detected counts of A.actinomycetemcomitans, P.intermedia, P.gingivalis, F.nucleatum and the total bacteria.
2. CH₃SH in the oral breath of the subjects showed a positive correlation with the detected count of P.gingivalis.
3. (CH₃)₂S in the oral breath of the subjects showed a positive correlation with the detected counts of A.actinomycetemcomitans, P.intermedia and total bacteria.
4. The concentrations of VSCs in the oral breath of the subjects showed a positive correlation with the total count of bacteria.
These results suggest that periodontopathic bacteria present in the tongue coat of healthy people might be the cause of physiological halitosis.

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C57L/J mice have about 90-100% incidence of gutter-shaped root (GSR) on the lower second molars (M2). Many investigators have reported the morphological features of this anomaly, but the development mechanisms are not well-understood. A classic genetic study on the cause of GSR in C57L/J mice suggested that a genetic factor with autosomal-dominant inheritance affected the development of mouse GSR. The purpose of this study was to identify genome regions of mouse GSR with novel method. We used N2 backcross mice (N = 153) from C57L/J mice, AKR/J mice and 103 informative polymorphic Mit (Massachusetts Institute of Technology) markers in this study. To evaluate phenotype, we calculate Dental root fusion rate (D.R.F.R.) using micro-CT. Here, quantitative trait locus (QTL) analysis was used to detect the chromosomal regions responsible for the mouse GSR in C57L/J mice. Highly significant value was obtained in the approximately 5.5 cM area from D6Mit284 (30.6 cM) to D6Mit230 (36.1 cM) on chromosome 6, strongly suggesting the existence of a major gene associated with the components of gutter-shaped root.

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Non-syndromic cleft lip with palate (CLP) represents one of the many craniofacial malformations identified in humans. The etiology underlying CLP are complex and highly variable. A/WySn mice serve as an intriguing model for human CLP, as they develop this dysmorphology with a variable expression pattern, incomplete penetrance and frequently demonstrate unilateral expression on a homogeneous genetic background. The developmental basis for these variations in expression is unknown. In the present study, the authors performed interval mapping and linkage analysis on the first backcross segregates of a cross between A/WySn and C57BL/6J (N₂ generation) mice affected with CLP using 99 informative Mit markers that have been previously determined. To ensure for the CLP trait, we observed mouse embryos on embryonic day 18 (E18), as palatal fusion does not occur prior to E16 in mice. 39 CLP affected individuals were identified in the 3,018 living N₂ backcross embryos. Two highly significant linkage regions on chromosome 11 (flanked by D11Mit245 and D11Mit203 markers) and chromosome 13 (flanked by D13Mit179 and D13Mit293 markers), respectively were obtained (χ², P < 0.001). These findings suggested that candidate genes for CLP in the A/WySn mouse strain are located on chromosomes 11 and 13.

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The aim of this clinical study was to evaluate the longitudinal changes in dental arches in patients treated with a slow maxillary expansion appliance in primary dentition or early mixed dentition. METHODS: The sample consisted of 19 children (13 girls and 6 boys) with a narrowing of the maxillary arch. The mean ages at the start, at the end of expansion, and at the final follow-up (1 year 7 months after the retention) were 7 years 10 months, 8 years 10 months and 12 years 4 months, respectively. The mean expansion period was 1 year and the mean retention period after the expansion was 1 year 11 months. The control group consisted of 28 Japanese persons with untreated normal occlusion. RESULTS: The results were as follows. (1) At the end of the expansion, the maxillary dental arch width increased remarkably, and there was no significant difference in comparison with the control group. (2) At the follow-up after the retention, although the maxillary intercanine width was significantly smaller than the control group, the maxillary intermolar width stabilized during retention and there was no significant difference in comparison with the control group. (3) The mandibular intermolar width gradually increased during the maxillary expansion. CONCLUSION: This clinical study demonstrated that this type of treatment using a slow maxillary expansion appliance in primary dentition or early mixed dentition is effective and stable in the long term for the maxillary molar regions. Furthermore, it was suggested that the lateral development of the mandibular dental arch could be promoted by expanding the maxillary dental arch width.

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In the present study, our purpose was to identify candidate gene(s) influencing initial dental caries susceptibility on chromosomes 7 and 11 using a Quantitative Trait Loci (QTL) analysis. On chromosome 7, five suggestive QTLs were detected in D7Mit31, D7Mit148, D7Mit262, D7Mit126 and D7Mit101. On chromosome 7, the peak LRS score was located in a region 50 cM from the centromere between marker D7Mit31 and PTH. On chromosome 11, five significant QTLs were detected in D11Mit242, D11Mit26, D11Mit339, D11Mit177 and D11Mit262. On chromosome 11, one highly significant QTL was detected in Kcnj12, the peak LRS score was located in a region 34.15 cM from the centromere marker Kcnj12. These results suggest that Kcnj12 on chromosome 11 might be one of the major gene(s) responsible for initial dental caries susceptibility.

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Idiopathic osteosclerosis (IO) is a localized, well-defined, intrabony radiopaque lesion within cancellous bone. The causes of IO are still unknown and most lesions are nonexpansile and asymptomatic, so they are often detected incidentally on radiographic examination for other purposes. In the case of jaw lesions, IO is considered to be of no clinical significance and usually requires no treatment. This paper describes two clinical cases about the long-term treatments and observations of mandibular IO in adolescents. The lesions were associated with abnormal tooth root formation and tooth malposition. In these cases, the orthodontic treatments finished successfully without any complication despite the lesions. IO in the jaw needs regular follow-up to ensure normal orofacial development during adolescence.

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Mucocele is a common oral mucosal lesion, but it is rarely observed in the infant. The aim of this study is to present the case report of a 1-year-old male patient, with a mucocele of the lower lip, describing the clinical characteristics and surgical treatment performed under local anesthesia with no recurrence observed after nine months follow-up, and also to show the histological features of this benign oral lesion.

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A 5Y7M-old girl was referred to our clinic by a general dentist for detailed examination of a recurrent gingival abscess in the maxillary left primary central incisor region. An intraoral examination revealed a diffuse swelling in the palatal gingiva area of the affected tooth. A periapical radiograph showed that the affected tooth was actually the primary central incisor and a supernumerary tooth, which had fused and been filled with composite resin at the juncture of the 2 tooth crowns. Removal of the filling induced severe bleeding and root canal treatment was performed. Radiographic examinations revealed 2 independent root canals, thus an additional access cavity to the mesial pulp cavity was produced for further root canal treatment. After the lesion had disappeared, root canal filling was performed using iodoform-calcium hydroxide paste and the affected tooth was restored with composite resin to fashion a single crown. However, the canal filling paste was later observed to be resorbed in the cervical area of the root. At 6Y0M, the patient received a traumatic injury in the anterior teeth region and the fused tooth was drastically displaced in a palatal direction, thus we extracted it under infiltration anesthesia. The root was observed to be wide in the mediodistal direction, and a histopathological examination revealed only dentin between 2 independent root canals. Our findings showed that the fused tooth was composed of 2 crowns and 1 root with 2 independent canals, and indicate that each crown and canal should have been treated separately.

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Regional odontodysplasia is an unusual non-hereditary developmental anomaly of tooth structures in both primary and permanent dentitions. The appropriate treatment differs for each individual’s clinical findings. The purpose of this study was to describe the clinical findings and the long-term progress as to the treatment and the management of a male patient who was diagnosed with regional odontodysplasia on the left side of the mandible. The mandibular left primary molars had shown a remarkable “ghost-like” appearance on x-ray, but they had already been extracted by an oral surgeon because of osteomyelitis due to pulpal infection, when the patient was referred to our pediatric dental clinic at 5 years of age. According to x-ray findings, the five permanent teeth (32, 33, 34, 35, 36) on the mandibular left side were delayed in formation. During the 15 years from age 5 to age 20, the patient was treated and managed in our clinic and the prosthodontic clinic of our hospital. Because the patient lost his mandibular left primary teeth early but presented delayed eruption of succedaneous permanent teeth, the patient used a temporary removable space maintainer for a long time. Although the affected first molar was extracted, the second premolar erupted and the other three unerupted teeth were not removed. The edentulous region was rehabilitated with a removable partial acrylic prosthesis when the patient was 19 years and 4 months. It was found that a multidisciplinary approach was essential for the long-term follow-up of typical regional odontodysplasia.

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Talon cusp and Dens invaginatus are tooth shape anomalies, their co-occurrence in a single tooth is rare. They are often incidental findings found during routine clinical and radiographic examinations. The patient is usually unaware of this condition unless detected radiographically. As maxillary lateral incisors are the teeth most susceptible to coronal invaginations and talon cusp these teeth should be investigated thoroughly. Early diagnosis is mandatory to instigate preventive treatment otherwise it might result in pulpal involvement necessitating more definitive treatment. We present here a case of bilateral coronal Dens invaginatus and true Talon treated prophylactically.

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