Caries and periodontitis are major oral diseases, both widespread and serious. Caries is thought to be caused by multifactorial, lifestyle-related factors as well as the genetic background of the patient. However, little is known about relevant genetic factors. Since the quality and quantity of enamel plays a direct role in the susceptibility to caries, we set out our quest for genetic factors from the two proteins crucial to the formation of dental enamel: amelogenin and enamelin. We isolated genomic DNAs from lingual mucosal cells derived from healthy and caries subjects, and examined the frequency of single nucleotide polymorphisms (SNPs) by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. We focused on the SNPs of the amelogenin gene (AMELX) at positions +287 and +522 (in both cases, a C to T substitution), and on position +2452 position of the enamelin gene (ENAM; here, too, a C to T substitution). The subjects were all of Japanese extraction, of which 67 individuals served as healthy controls and 80 patients with severe caries served as test subjects. The occurrence of the substitutions at AMELX(+287), (+522) and ENAM(+2452) were 12.2, 0.0 and 11.9% in the control group, and 2.5, 0.0 and 5.0% in the caries group, respectively. The P-values for the statistical frequency of SNPs for AMELX(+287) and ENAM(+2452) were 0.142 and 0.143, respectively. Our data suggest that there was no significant association between the SNPs of those genes and caries susceptibility in the Japanese pediatric population.

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Tooth infractions are regarded as possible pathways for microorganisms and other pulpal irritants in gaining access to the dental pulp; hence, these defects must be sealed to prevent subsequent pulpal involvement. This study aims to examine the structure of experimentally formed visible infractions and evaluate the penetration of resin into infractions after the application of resin onto the tooth surface that contains such defects. In experiment 1, porcine premolars were subjected to impaction procedures to create infractions and transverse ground sections were prepared to study the structure of the defect. In experiment 2, penetration of resin was evaluated. Another set of specimens were subjected to the same impaction procedure. These teeth received the application of 4 META/MMA-TBB resin and sectioned horizontally. The exposed surfaces were initially immersed in HCl then stained with Toluidine blue and subsequently with Fuchsin. For SEM examination, another tooth specimen was subjected to impaction procedure and prepared similarly with experiment 2. The results show that microscopically, infractions were wider than enamel lamellae, and some reached deep into the dentine. The penetrated resin was identified as a structure that stained with both Toluidine blue and Fuchsin in all infractions. The average penetration depth was 338.83±138 μm and is not related to enamel layer thickness. SEM examination revealed that the outlines of surrounding enamel rods were visible as imprinted on the surface of the penetrated resin. In conclusion, the present results suggest that resin may adequately seal the infractions, thus prevent the ingress of pulpal irritants via these defects. Therefore, it is recommended that the tooth should be covered with dental adhesive resin as soon as possible after trauma.

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The purpose of this study was clarify the morphological condition of occlusal grooves in the maxillary first and second deciduous molars with micro-CT. We took photographs of the maxillary deciduous molars using a micro-CT device and reconstructed the three-dimensional image of the anatomical crown using a three-dimensional visualization and measurement software. For observation and measurement of the occlusal grooves, two-dimensional sliced images were generated 10 images at each groove. On the generated two-dimensional sliced images, we measured the occlusal angle, the depth of the occlusal groove and the enamel thickness at its bottom. The sites which showed smallest angle were distal portions of the central groove in maxillary first deciduous molar, and lingual groove in maxillary second deciduous molar. The occlusal groove in maxillary second deciduous molar was deeper than that of maxillary first deciduous molar in all sites examined, except for distal portion of the central groove. The enamel thickness in maxillary second deciduous molars tended to have thicker enamel than that of first deciduous molars. In maxillary first deciduous molars, most of the occlusal grooves exhibited the shape classified into type P. Whereas in maxillary second deciduous molars, the ratio of type P was relatively low, especially, lingual grooves consisted of type V, whose angle was less than 90 degree, type U and type I, which had the shape looked like a stick. Distal portion of the central groove of maxillary first deciduous molar, and lingual groove of maxillary second deciduous molar tend to be the initiation and predilection sites of dental caries due to the anatomical features of their occlusal fissures. Moreover, it is preferable to apply pit and fissure sealant into the occlusal fissures containing this region at an early point of the treatment.

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In pedodontic practice, children with deciduous anterior crossbite are frequently encountered. In treating deciduous anterior crossbite, determining the optimal time to start treatment and predicting the prognosis of treatment are very important. We investigated the pre-treatment morphological characteristics of craniofacial complex and dentition of children with deciduous anterior crossbite who showed favorable prognoses and avoided relapse even after growth and development were completed. The subjects consisted of 7 boys and 12 girls with deciduous anterior crossbite before treatment. The subjects were divided into those without relapse (n = 13) and those with relapse (n = 6) and these two groups were compared using their lateral cephalometric radiographs and study models. The following characteristics were demonstrated in the children without relapse: (1) There was no family history of anterior crossbite. (2) There were no significant differences between two groups in the width or length of mandibular dental arch. (3) Anterior facial height was not longer than the standard value. (4) On angular analysis, the variable with the most conspicuous difference between the non-relapsed prognosis group and relapse group was the NSAr angle (Saddle angle). The value of this angle in the non-relapsed prognosis group was close to the standard value. This retrospective study indicates that early proactive treatment for deciduous anterior crossbite is considered suitable for children with the above characteristics.

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The outcome of replantation of traumatically avulsed teeth depends largely on the immediate and appropriate management. However most dental injuries happen in the home or at school, where immediate treatment is not usually available. The objective of this study was to assess the knowledge and attitudes among guardians and children in Japan about tooth injuries, the management of avulsed teeth, and mouthguards. An 18-item questionnaire (3 general items about tooth injuries, 8 about the management of avulsed teeth and 7 about mouthguards) was distributed to 256 guardians and 92 children at the Pediatric Dental Clinic of Niigata University Dental Hospital. One-third of the respondents reported having had a tooth injury, but most had never been advised about the importance of emergency management in dental injuries. On the other hand, 185 guardians (72%) but only 21 children (23%) indicated an interest in taking an educational course about dental injuries. Approximately 75% of the respondents did not know that avulsed teeth could be replanted. Moreover, less than 20% knew that the best way to store avulsed teeth at home was to soak them in milk. Forty-five percent of those with this knowledge had obtained the information from TV programs, whereas only 10% received it from their dentist. As to mouthguards, while nearly 70% of the respondents knew what mouthguards are, only 13% of the children planned to use a mouthguard while playing sports, whereas 30% of the guardians reported that they would require their children to wear one during sports. This study revealed the need for educational campaigns to increase lay people’s knowledge of emergency treatment for avulsed teeth and to encourage children to use mouthguards while playing baseball and basketball.

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The bite force prior to orthodontic treatment was determined to examine whether occlusal and masticatory functions in children with cleft lip and/or palate (CL/P), but with most teeth participating in occlusion, are inferior to those in children with normal occlusion without CL/P. The subjects were 31 children (20 boys and 11 girls) with CL/P and 26 children (10 boys and 16 girls) with normal occlusion without CL/P. All the children were 4 years old. To examine occlusal function, we measured the occlusal contact area, bite pressure, and bite force using bite pressure detection film “dental prescale” (R-type) and the “Occluser” system (Fuji Photo Film Co.). The average and maximum bite pressures in children with CL/P were significantly higher than those for children with normal occlusion without CL/P. The bite pressure and bite force in children with CL/P were similar to or greater than those for children with normal occlusion without CL/P, provided that the children with CL/P had only a slightly asymmetric dental arch and that most teeth participated in occlusion. These results suggest that occlusion functions in children with CL/P are not inferior to those of children with normal occlusion without CL/P.

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We hypothesized that patients with Cerebral Palsy (CP) are affected by the preparatory process in the central nervous system for initiating a jaw movement. We tested this hypothesis on 13 in patients with CP (average: 36.9 years old) and 13 in healthy adults (average: 34.7 years old) as subjects. We recorded the muscular discharge of the masticatory muscles from the time a warning stimulus was presented to the time an instruction stimulus was presented during the reaction time (RT) with the open mouth movements in patients with CP. The following results were obtained. The RT for executing the open mouth movements is significantly longer in the CP subjects than in the healthy subjects. In the CP subjects during the movement task, the level of muscular discharge of the masticatory muscles in the 1-s period before presentation of a warning stimulus was significantly lower than that in the 1-s period or in the period from 1 s to 2 s after the presentation of the warning stimulus. The other side, In the healthy subjects, no change in the muscular discharge of the masticatory muscles was observed. However, In the CP subjects and in the healthy subjects during the nonmovement task, no change in the level of muscular discharge of the masticatory muscles in each period was observed. A significant correlation was observed between the percent change of the level of muscular discharge of the masseter muscle (or the digastric muscle) and RT for the open mouth movement. From the results of this study, as one of the reasons for the difficulty in executing smooth voluntary movements in the oromandibular region in individuals with CP, we consider that the movement is delayed because the period of preparation of the movement is significantly prolonged in individuals with CP although they started the preparation of the movement at an earlier period than in individuals who do not have CP.

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The ability to discriminate the sensation of the mandibular position in the cerebral palsy (CP) patients was studied and the relationship between this ability to discriminate the sensation of the mandibular position and the oral dysfunctions was evaluated. Interdental dimension discrimination tests (IDD test) were performed in order to evaluate the ability to discriminate the sensation of the mandibular position in 18 CP patients and in 15 healthy individuals. Using the test result, points of subjective equality (PSE) and difference limen (DL) were obtained. In addition, the oral dysfunction index was used to evaluate the oral dysfunctions of the CP patients. The results obtained are as follows
1) PSE in the CP patients was significantly lower than that in the healthy individuals.
2) No significant difference was observed in DL between the CP patients and healthy individuals.
3) A significant correlation was observed between PSE and ODI in the CP patients.

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Dental diseases in young children are closely related to lifestyle, hence it is difficult to identify a single causative factor. To prevent and control dental diseases in young children, EBM-based indicators for maintaining and promoting oral health can be established by elucidating the relationships among factors including “host”, “oral cavity environment”, “dental hygiene”, “diet”, “snack eating”, and “others”. The author conducted an epidemiological study in young children (3-6 years) to determine accurate indicators for dental health guidance to help prevent dental diseases, and performed clinical epidemiological analysis and evaluation to examine the relationships between each factor using logistic regression analysis. The results showed that 3 items, “severe PMA”, “severe CAT” and “not undergoing regular dental check-ups” boosted dmf (decayed missing filled) where significance was observed in the odds ratio for all children. The 3 items boosted PMA and significance was observed in odds ratio in all children for “severe dmf”, “severe CAT”, and “snack eating”. These results suggested a correlation between dental caries and gingivitis development, and the correlation was more significant at an earlier age. The results also suggested that CAT is an effective testing method, not only for dental caries but for plaque-induced gingivitis in young children.

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The objective of this study was to evaluate the knowledge, attitude and behavior of Greek elementary school students in terms of oral health and dental care. Data on students’ oral health and dental treatment as well as, the factors that define these variables were collected and evaluated by a self-administered questionnaire for a sample of 595 students. The results revealed that irregular brushing was common. Apart from the use of toothbrush and toothpaste, extra aids for oral hygiene were also in use. The role of parents in supervising the oral hygiene habits of their children was concentrated only in giving advice. The students knew the causes of gingivitis and caries and how to protect their dental health. Also, they were aware of the mouth and dental structure on the general body health. Toothache was the driving reason of visiting the dentist. Irregular visits to the dentist were mentioned, even though they knew the importance of regular dental visits. The feeling of fear, in general, and fear of dental tools and dental wheel were referred to be the main reason for not visiting the dentist on a regular basis. Students were not encouraged by their parents for regular dental visits. The outcomes of this study show that Greek elementary students knowledge, attitude and behavior towards oral health and dental care need to be improved through oral health behavior programs.

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An 11-month-old boy with a talon cusp in the maxillary right primary central incisor is reported. The patient came to our hospital with an abnormal tooth morphology. An intraoral examination showed that 8 teeth had emerged into the oral cavity, among which 1 tooth was identified with the cusp-like structure on the palatal side that extended from the cingulum to the incisal edge and appeared to be T-shaped in the occlusal view. The incisal edge of the affected tooth was displaced labially and the cusp-like structure was located in the dental arch. Since there were no signs or symptoms to be treated immediately, we decided to carry out periodical examinations. As the patient aged, the height of the cusp decreased. The horn-like extended pulp space was identified in radiographs taken at the age of 3Y0M and 5Y5M. There have been no other signs or symptoms of the affected tooth, except for labial displacement, during the 4.5-year follow-up period.

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47, XYY is a sex chromosome-number disorder occurring in males. Pediatric dentists seldom report encountering 47, XYY males, probably because there are no overt signs of the disease. The purpose of this report is to present the clinical oro-facial findings of the case of a 47, XYY boy based on cephalometric analysis and study model examinations as well as micro-CT measurement of tooth mineralization. An 11-year-old Japanese boy was referred to our clinic for extraction of primary teeth because of their prolonged retention. He had 47, XYY disorder, pulmonary hypertension, and slight mental retardation. Cephalometric analysis and study model examinations that included a comparison of tooth size and arch assessments were performed. A further attempt was made to demonstrate the degree of dentin mineralization in primary molars. The boy’s height and weight were normal but his head circumference had exceeded the 94th percentile since 2 years of age. The cephalometric analysis showed an increase in the lower facial height and bimaxillary protrusion with a longer mandible. Study model examination revealed that the mesio-distal crown widths of all erupted primary and permanent teeth were larger than the standard values, except for the mandibular permanent canines. The degree of dentin mineralization was almost normal in the crown and root areas. A profilogram showed an increase in the lower facial height and bimaxillary protrusion with a longer mandible. The dental arch showed a remarkably contracted width but an extended length. The crown width was larger than the standard values, but the distribution of the degree of dentin mineralization differed little from normal.

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We present a case of Sotos syndrome. A 2-year-1-month-old Japanese boy diagnosed with Sotos syndrome was referred to our clinic for an oral examination. His growth from birth to the age of 4 years 11 months was pronounced above the 97th percentile. The primary teeth erupted extremely early, with the lower central incisors appearing at the age of 5 months, and all the primary teeth except the lower lateral incisors erupted by the age of 2 years 1 month. In addition, the lower permanent first molar erupted at the age of 4 years 6 months. However, mean dental age did not advance with chronological age. The tooth morphology appeared to be normal, however, the primary teeth were easily degraded by attrition, suggesting the poor calcification. A radiographic examination showed congenital missing of the lower primary and permanent lateral incisors, second premolars, and upper first premolars. In addition, the roots of the primary molars were extremely long and the ration of root length to crown length shown in panoramic radiographs was high.

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Dens invaginatus and dens evaginatus are dental developmental variations of shape that usually occur in isolation but can be observed in association with other dental anomalies. However, no publications have reported the same patient with maxillary lateral incisors affected one by dens evaginatus (right side) and the other by dens invaginatus (left side). This article presents a case of an 8-year-old boy with the presence of abnormal crown morphology in unerupted permanent maxillary lateral incisors. The right maxillary incisor revealed dens evaginatus and the left maxillary incisor presented dens invaginatus. The treatment plan consisted of following up the eruption of maxillary lateral incisors and prophylactic restorative procedure.

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We presented a case of an intractable periapical abscess in the area of the maxillary first molar. The tooth had no evidences of dental caries, restoration, or fracture, and responded well to a pulp vitality test. However, a radiographic examination revealed radiolucency in the apical portion of the distal root. Computerized tomography (CT) revealed that the tooth had 1 buccal and 2 palatal roots fused together, expressing a U-shaped. Further, a radicular groove that reached to the crown portion of the distal surface was found. Radiolucency was observed in the area adjacent to the radicular groove and in the U-shaped region. We finally performed an intentional replantation, since conventional periodontic and endodontic procedures were unsuccessful. One year postoperatively, the patient had no clinical or radiographic symptoms.

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We treated a case of eruption sequestrum in an 8-year 1-month old boy. The patient first came to our clinic with a chief complaint of discomfort in the mandibular left first molar region. An intraoral examination revealed a small hard tissue fragment on the occlusal surface of the erupting mandibular left first molar, while a periapical radiograph showed a bone-like radiopaque mass. We diagnosed the lesion as eruption sequestrum, and removed it under topical anesthesia. A histopathological examination of the sectioned extirpated tissue showed necrotic cortical bone without osteocytes within the lacunae. Although eruption sequestra are occasionally encountered in daily practice, there is a limited number of reports describing details of specific cases, with only 14 known cases reported in literature. Herein, we report our findings and summarize those in other reports based on clinical, radiographic and histopathological findings.

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Aicardi syndrome is a rare neurodevelopment disorder characterized by agenesis of the corpus callosum, other developmental brain abnormalities, chorioretinal lacunae, severe seizures, and cleft lip and palate (CLP). This syndrome has been observed only in female due to be caused by an X-linked dominant gene that is lethal in hemizygous males. There has not been reported about the presurgical nasoalveolar molding (PNAM) treatment for Aicardi syndrome patient with CLP, although the importance of PNAM treatment for cleft lip is widely recognized. The purpose of this report was to present PNAM treatment for the case of Aicardi syndrome with CLP, along with a pertinent review of the literature, comparison to similar case reports, and to describe for the process of PNAM treatment in this syndrome.

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A 10 year-3 month-old boy with root resorption of the right central incisor associated with impaction of the right canine in the maxilla was referred to our dental clinic by a private general dental practitioner. He had Down syndrome with slight intellectual impairment and no congenital heart disease. Since the results of the mental development age test indicated that his development age was probably more than 4 years and 8 months, we decided that we could treat the patient by using behavior management techniques. We explained the procedures for comprehensive dental treatment in a simplified manner to the patient by using behavior management techniques. The use of enhanced behavior management techniques enabled him to accept comprehensive dental treatment that included extraction of the central incisor and orthodontic and restorative treatments of the impacted canine. We were able to complete the treatments and obtain a good outcome.

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Rett syndrome (RTT) was neurological disorder which affects usually female. They have severe autism, loss of purposeful use hand, weight loss and epilepsy. Previous dental reports suggested that RTT patient frequently have bruxism, and they recommended biteplate therapy for tooth protection from bruxism. However, we did not find any physiological approach of bruxism in patient with RTT. Here we first report of bruxism status of RTT by using EMG analysis, biteplate therapy, and make evidence of it. The masseter muscle EMG activity was statistically significant reduced after template therapy. This data was scientifically evidence that template therapy was useful tool for protect form tooth wear caused bruxism with RTT patient.

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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.

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